[CI] InferenceRestIT test {p0=inference/30_semantic_text_inference/Calculates embeddings using the default ELSER 2 endpoint} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #4966 / rhel-7_platform-support-unix
• elasticsearch-periodic #4977 / encryption-at-rest
• elasticsearch-periodic #4971 / concurrent-search-tests
• elasticsearch-periodic-platform-support #4947 / rhel-9_platform-support-unix
• elasticsearch-periodic-platform-support #4890 / debian-11_platform-support-unix

Reproduction Line:

./gradlew ":x-pack:plugin:inference:yamlRestTest" --tests "org.elasticsearch.xpack.inference.InferenceRestIT.test {p0=inference/30_semantic_text_inference/Calculates embeddings using the default ELSER 2 endpoint}" -Dtests.seed=57576770F7735DD4 -Dtests.locale=ia-Latn-001 -Dtests.timezone=Atlantic/Madeira -Druntime.java=23

Applicable branches: 8.16

Reproduces locally?: N/A

Failure History: See dashboard&_a=(controlGroupState:(initialChildControlState:('0c0c9cb8-ccd2-45c6-9b13-96bac4abc542':(dataViewId:fbbdc689-be23-4b3d-8057-aa402e9ed0c5,fieldName:task.keyword,order:0,selectedOptions:!(),title:'GradleTask',type:optionsListControl),'4e6ad9d6-6fdc-4fcc-bf1a-aa6ca79e0850':(dataViewId:fbbdc689-be23-4b3d-8057-aa402e9ed0c5,fieldName:className.keyword,order:1,selectedOptions:!(org.elasticsearch.xpack.inference.InferenceRestIT),title:'Suite',type:optionsListControl),'144933da-5c1b-4257-a969-7f43455a7901':(dataViewId:fbbdc689-be23-4b3d-8057-aa402e9ed0c5,fieldName:name.keyword,order:2,selectedOptions:!(test%20%7Bp0%3Dinference%2F30_semantic_text_inference%2FCalculates%20embeddings%20using%20the%20default%20ELSER%202%20endpoint%7D),title:'Test',type:optionsListControl)))))

Failure Message:

java.lang.RuntimeException: Failure at [inference/30_semantic_text_inference:570]: 120.000 milliseconds timeout on connection http-outgoing-1 [ACTIVE]

Issue Reasons:

• [8.16] 5 failures in test test {p0=inference/30_semantic_text_inference/Calculates embeddings using the default ELSER 2 endpoint} (1.1% fail rate in 472 executions)
• [8.16] 3 failures in pipeline elasticsearch-periodic-platform-support (20.0% fail rate in 15 executions)
• [8.16] 2 failures in pipeline elasticsearch-periodic (13.3% fail rate in 15 executions)

Note: This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

Pinging @elastic/ml-core (Team:ML)

[Mikep86]

Muting this flaky test in all relevant branches until it is fixed: https://github.com/elastic/elasticsearch/pull/117390