[Upgrade assistant]Upgrade assistant doesn't format the date format exception and doesn't show remediation steps

[bhavyarm]

Kibana version: 8.18.0 Snapshot

Elasticsearch version: 8.18.0 Snapshot

Browser version: Chrome latest

Browser OS version: OS X

Original install method (e.g. download page, yum, from source, etc.): from snapshots

Describe the bug: If user has indices with older compat format fields, upgrade assistant shows critical deprecation issue for this and reindex fails (requires manual script correction(https://www.elastic.co/blog/locale-changes-elasticsearch-8-16-jdk-23) - but doesn't show any remediation steps on the assistant itself.

Steps to reproduce:

1. Ingest data with old data format in 8.16.x

PUT books
{
  "mappings": {
    "properties": {
      "release_date": {
        "type":   "date",
        "format": "EEEE dd MMMM yyyy GGG"
      },
      "release_date_2": {
        "type":   "date",
        "format": "EEEE dd MMMM yyyy h:mm B"
      },
      "release_date_3": {
        "type":   "date",
        "format": "qqqq yyyy"
      },
      "release_date_de": {
        "type":   "date",
        "format": "EEE dd MMM yyyy GGGGG",
        "locale": "de"
      },
      "release_date_ja": {
        "type":   "date",
        "format": "dd MMM yyyy",
        "locale": "ja"
      }
    }
  }
}

Ingest some sample documents:

POST /_bulk
{"index":{"_index":"books"}}
{"name":"Revelation Space","author":"Alastair Reynolds","release_date":"Tuesday 17 September 2024 AD","release_date_2":"Tuesday 17 September 2024 7:30 AM","release_date_3":"3 2024","release_date_de":"Di 17 Sep 2024 A","release_date_ja":"17 9 2024","page_count":585}
{"index":{"_index":"books"}}
{"name":"1984","author":"George Orwell","release_date":"Wednesday 18 September 2024 AD","release_date_2":"Wednesday 18 September 2024 8:30 AM","release_date_3":"1 2024","release_date_de":"Mi 18 Sep 2024 A","release_date_ja":"18 9 2024","page_count":328}
{"index":{"_index":"books"}}
{"name":"Fahrenheit 451","author":"Ray Bradbury","release_date":"Monday 16 September 2024 AD","release_date_2":"Monday 16 September 2024 8:30 AM","release_date_3":"2 2024","release_date_de":"Mo 16 Sep 2024 A","release_date_ja":"16 9 2024","page_count":227}
{"index":{"_index":"books"}}
{"name":"Brave New World","author":"Aldous Huxley","release_date":"Sunday 15 September 2024 AD","release_date_2":"Sunday 15 September 2024 5:30 AM","release_date_3":"2 2024","release_date_de":"So 16 Sep 2024 A","release_date_ja":"15 9 2024","page_count":268}
{"index":{"_index":"books"}}
{"name":"The Handmaids Tale","author":"Margaret Atwood","release_date":"Saturday 14 September 2024 AD","release_date_2":"Saturday 14 September 2024 4:30 AM","release_date_3":"4 2024","release_date_de":"Sa 16 Sep 2024 A","release_date_ja":"14 9 2024","page_count":311}

2. Upgrade to 8.18.x
3. The upgrade assistant shows books index needs to be reindexed and if you click on reindex fails with an error which isn't formatted and no remediation steps.

Error:

Reindexing error

Error: Reindexing failed: {"completed":true,"task":{"node":"IYA5ReTVTKKo38sGA452lw","id":745759,"type":"transport","action":"indices:data/write/reindex","status":{"total":5,"updated":0,"created":0,"deleted":0,"batches":1,"version_conflicts":0,"noops":0,"retries":{"bulk":0,"search":0},"throttled_millis":0,"requests_per_second":-1,"throttled_until_millis":0},"description":"reindex from [books] to [reindexed-v8-books]","start_time_in_millis":1734453342305,"running_time_in_nanos":12691250,"cancellable":true,"cancelled":false,"headers":{"X-elastic-product-origin":"kibana","trace.id":"d8ab0425ed518bf6b78e54b58d03d1f5","X-Opaque-Id":"7ffc4a30-e5e3-43eb-b491-c8c6952defc8;kibana:application:management:"}},"response":{"took":12,"timed_out":false,"total":5,"updated":0,"created":0,"deleted":0,"batches":1,"version_conflicts":0,"noops":0,"retries":{"bulk":0,"search":0},"throttled":"0s","throttled_millis":0,"requests_per_second":-1,"throttled_until":"0s","throttled_until_millis":0,"failures":[{"index":"reindexed-v8-books","id":"uKrwC5IBJd_B63XbLGr-","cause":{"type":"document_parsing_exception","reason":"[1:173] failed to parse field [release_date_3] of type [date] in document with id 'uKrwC5IBJd_B63XbLGr-'. Preview of field's value: '3 2024'","caused_by":{"type":"illegal_argument_exception","reason":"failed to parse date field [3 2024] with format [qqqq yyyy]","caused_by":{"type":"date_time_parse_exception","reason":"Text '3 2024' could not be parsed at index 0"}}},"status":400},{"index":"reindexed-v8-books","id":"uarwC5IBJd_B63XbLGr-","cause":{"type":"document_parsing_exception","reason":"[1:161] failed to parse field [release_date_3] of type [date] in document with id 'uarwC5IBJd_B63XbLGr-'. Preview of field's value: '1 2024'","caused_by":{"type":"illegal_argument_exception","reason":"failed to parse date field [1 2024] with format [qqqq yyyy]","caused_by":{"type":"date_time_parse_exception","reason":"Text '1 2024' could not be parsed at index 0"}}},"status":400},{"index":"reindexed-v8-books","id":"uqrwC5IBJd_B63XbLGr-","cause":{"type":"document_parsing_exception","reason":"[1:164] failed to parse field [release_date_3] of type [date] in document with id 'uqrwC5IBJd_B63XbLGr-'. Preview of field's value: '2 2024'","caused_by":{"type":"illegal_argument_exception","reason":"failed to parse date field [2 2024] with format [qqqq yyyy]","caused_by":{"type":"date_time_parse_exception","reason":"Text '2 2024' could not be parsed at index 0"}}},"status":400},{"index":"reindexed-v8-books","id":"u6rwC5IBJd_B63XbLGr-","cause":{"type":"document_parsing_exception","reason":"[1:166] failed to parse field [release_date_3] of type [date] in document with id 'u6rwC5IBJd_B63XbLGr-'. Preview of field's value: '2 2024'","caused_by":{"type":"illegal_argument_exception","reason":"failed to parse date field [2 2024] with format [qqqq yyyy]","caused_by":{"type":"date_time_parse_exception","reason":"Text '2 2024' could not be parsed at index 0"}}},"status":400},{"index":"reindexed-v8-books","id":"vKrwC5IBJd_B63XbLGr-","cause":{"type":"document_parsing_exception","reason":"[1:175] failed to parse field [release_date_3] of type [date] in document with id 'vKrwC5IBJd_B63XbLGr-'. Preview of field's value: '4 2024'","caused_by":{"type":"illegal_argument_exception","reason":"failed to parse date field [4 2024] with format [qqqq yyyy]","caused_by":{"type":"date_time_parse_exception","reason":"Text '4 2024' could not be parsed at index 0"}}},"status":400}]}}

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)