Missing external_identifier source

[ctgraham]

Describe the bug

Error transforming agent_person /agents/people/2189: 'local' is not valid under any of the given schemas

Failed validating 'oneOf' in schema['allOf'][0]['properties']['external_identifiers']['items']['allOf'][0]['properties']['source']:
    {'examples': ['wikidata', 'archivesspace'],
     'oneOf': [{'$ref': '#/definitions/source'}],
     'pattern': '^(.*)$',
     'title': 'External Identifier Source',
     'type': 'string'}

On instance['external_identifiers'][0]['source']:
    'local'
Unable to send error notification email: [Errno -2] Name or service not known
2146 records exported in 0:05:36.627542
1 errors
    Error transforming agent_person /agents/people/2189: 'local' is not valid under any of the given schemas

Failed validating 'oneOf' in schema['allOf'][0]['properties']['external_identifiers']['items']['allOf'][0]['properties']['source']:
    {'examples': ['wikidata', 'archivesspace'],
     'oneOf': [{'$ref': '#/definitions/source'}],
     'pattern': '^(.*)$',
     'title': 'External Identifier Source',
     'type': 'string'}

On instance['external_identifiers'][0]['source']:
    'local'

Additional context

rac_schemas/rac_schemas/schemas/base.json

Lines 146 to 157 in c8a79c2

	"source": {
	"type": "string",
	"title": "External Identifier Source",
	"examples": [
	"wikidata",
	"archivesspace"
	],
	"pattern": "^(.*)$",
	"oneOf": [{
	"$ref": "#/definitions/source"
	}]
	},

refers to:

rac_schemas/rac_schemas/schemas/base.json

Lines 465 to 480 in c8a79c2

	"source": {
	"$id": "#/definitions/source",
	"type": "string",
	"enum": [
	"archivesspace",
	"cartographer",
	"wikidata",
	"wikipedia"
	],
	"title": "Sources",
	"description": "Source of item",
	"minLength": 1,
	"examples": [
	"cartographer"
	]
	},