[ML] Increase Test Coverage 8.17.0

Meta issue to summarize improvements to test coverage for 8.17.0.

Jest unit tests

[ ] DELETE /internal/ml/datafeeds/:datafeedId
[ ] GET /internal/ml/trained_models/ingest_pipelines (DA) (look to remove this endpoint)
[ ] POST /internal/ml/trained_models/create_inference_pipeline (DA) (look to remove this endpoint)
[ ] POST /internal/ml/anomaly_detectors/_validate/detector (JG) (remove endpoint) https://github.com/elastic/kibana/pull/198667
[ ] Move some AIOps API tests to the deployment agnostic (serverless and stateful) folder

[x] Memory usage page (include check for memory usage chart) (RJ) https://github.com/elastic/kibana/pull/197415
[x] Log rate analysis embeddable (WR) https://github.com/elastic/kibana/pull/197943
[x] Log rate analysis - search bar edit (MA) https://github.com/elastic/kibana/pull/199054
[ ] SMV: Assert that it should not show a chart until the partition field is selected (DA) https://github.com/elastic/kibana/pull/189729#issuecomment-2288581171
[ ] SMV: Assert annotations and anomalies table content. https://github.com/elastic/kibana/pull/189729#issuecomment-2288722912 (at the moment we only assert if exists)
[ ] AD jobs list: Stop datafeed action https://github.com/elastic/kibana/pull/189729#issuecomment-2288679629

part of #88496