[ML] Remove unsupported project_routing from clear job audit messages

[wildemat]

Summary

Clearing ML anomaly detection job notifications fails with an HTTP 400 on serverless projects with CPS enabled:

parsing_exception: Unknown key for a VALUE_STRING in [project_routing]

clearJobAuditMessages passed project_routing into asInternalUser.updateByQuery(...) and asInternalUser.index(...). Neither Elasticsearch API accepts that parameter, and the ES client just forwarded the unrecognized params.

• update_by_query: 400 when this function sends project_routing to ES query body
• index: project_routing was just written into the _source of the index's documents for this case. So index documents up until now that have hit this issue don't need to be cleaned up.

The three search calls in the same file keep their project_routing, because they declare project_routing in acceptedParams

Core's CPS request handler already injects project_routing automatically for APIs that accept it (acceptedParams). Removing these manual spreads won't regress anything.

Type issue

Typecheck didn't catch it because conditional spread operator doesn't trip excess property check.

UpdateByQueryRequest and IndexRequest do not declare project_routing; SearchRequest, FieldCapsRequest and MsearchRequest do.

Testing

New job_audit_messages.test.ts with three cases:

1. updateByQuery receives no project_routing.
2. index receives no project_routing, on params or the document body.
3. search still receives project_routing

Two new tests failed on latest main changes and passed after these changes.

Closes https://github.com/elastic/sdh-kibana/issues/6491
Regression introduced by #251270

Checklist

• Unit or functional tests were updated or added to match the most common scenarios
• The PR description includes the appropriate Release Notes section, and the correct release_note:* label is applied per the guidelines
• Review the backport guidelines and apply applicable backport:* labels.

Not applicable: no user-facing text (no i18n), no documentation changes, no plugin configuration keys, no HTTP API changes, no existing tests changed (only new tests added, so no Flaky Test Runner run).

Identify risks

Low risk. This removes a parameter that the two affected Elasticsearch APIs never accepted, and which Core injects automatically where it is accepted.

Made with Cursor, further reviewed and edited by @wildemat

[infra-vault-gh-plugin-prod]

Pinging @elastic/ml-ui (:ml)

[kibanamachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: dd587bb
• Build duration: 59 mins
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Failed CI Steps

• FTR Configs #78
• Scout Lane #15 - stateful-classic / default

Metrics [docs]

✅ unchanged

Test Failures

• [job] [logs] Scout Lane #15 - stateful-classic / default / local-stateful-classic - Dataset quality - data stream stats across data stream types - returns the stats of every requested data stream type
• [job] [logs] FTR Configs #78 / visualize app annotation listing page edit data view switching recovers from missing field in data view

[jgowdyelastic]

LGTM