[Streams] Add curl example to Logs Stream onboarding

[LucaWintergerst]

similar to the docs change, let's add one tab with the same curl snippet:

elastic/docs-content#3683

[elasticmachine]

Pinging @elastic/obs-ux-logs-team (Team:obs-ux-logs)

[flash1293]

The tabs in x-pack/platform/plugins/shared/streams_app/public/components/stream_list_view/streams_settings_flyout.tsx need to be extended for this. The tab should be called curl, the content should be

POST /logs/_bulk
{ "create": {} }
{ "@timestamp": "2025-05-05T12:12:12", "body": { "text": "Hello world!" }, "resource": { "attributes": { "host.name": "my-host-name" } } }
{ "create": {} }
{ "@timestamp": "2025-05-05T12:12:12", "message": "Hello world!", "host.name": "my-host-name" }