[Obs AI Assistant] Add support for dense vector embeddings in API tests

[sorenlouv]

This adds support for the tiny_text_embedding model that generated dense vector embeddings in API tests. This will be useful when we support multiple models and need to confirm that we can switch between models, and embeddings are correctly updated.

Also adds some small refactorings/cleanup

[viduni94]

Added one comment. The rest LGTM.
Thanks @sorenlouv

[viduni94]

In the route definition for /internal/ml//trained_models/{modelId}/deployment/_start the path param seems to be the modelId and deploymentId is an optional query param.

I'm not sure whether the /_ml/trained_models/${deploymentId}/deployment/_start definition is different from the /internal/ml/trained_models/{modelId}/deployment/_startl definition.

If it's the same, can we call this modelId instead of deploymentId for clarity?

Suggested change

	async startTrainedModelDeploymentES(deploymentId: string) {
	async startTrainedModelDeploymentES(modelId: string) {

[kibanamachine]

Starting backport for target branches: 8.19

https://github.com/elastic/kibana/actions/runs/14711737381

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 6b9f89d

Failed CI Steps

• Jest Tests #1

Test Failures

• [job] [logs] Jest Tests #1 / MlUserJobDescription should render toast that shows admin permissions required

Metrics [docs]

✅ unchanged

History

• 💔 Build #296535 failed 8855faf
• 💔 Build #296531 failed facb4dd

[kibanamachine]

💔 All backports failed

Status	Branch	Result
❌	8.19	Backport failed because of merge conflicts

Manual backport

To create the backport manually run:

node scripts/backport --pr 219199

Questions ?

Please refer to the Backport tool documentation

[kibanamachine]

Friendly reminder: Looks like this PR hasn’t been backported yet.
To create automatically backports add a backport:* label or prevent reminders by adding the backport:skip label.
You can also create backports manually by running node scripts/backport --pr 219199 locally
cc: @sorenlouv

[kibanamachine]

Friendly reminder: Looks like this PR hasn’t been backported yet.
To create automatically backports add a backport:* label or prevent reminders by adding the backport:skip label.
You can also create backports manually by running node scripts/backport --pr 219199 locally
cc: @sorenlouv