Use SdkClient for persistence in MonitorMetadataService

[manaswini1920]

Description

Migrates MonitorMetadataService.upsertMetadata() and getMetadata() to use SdkClient instead of direct OpenSearch client calls, as part of the remote metadata SDK migration for background services.

Changes:

• MonitorMetadataService.upsertMetadata(): Replaced IndexRequest with PutDataObjectRequest via sdkClient.putDataObjectAsync()
• MonitorMetadataService.getMetadata(): Replaced GetRequest with GetDataObjectRequest via sdkClient.getDataObjectAsync()
• AlertingPlugin.kt: Set sdkClient on MonitorMetadataService after SDK client creation
• SdkUtils.kt: Added suspend fun CompletionStage.await() helper for coroutine-safe SDK calls (same as Use SdkClient for persistence in IndexAlertingComment, IndexMonitor #2081)

Notes:

• createFullRunContext() calls (getIndex, indicesStats) are admin/infrastructure operations and remain on direct client
• Routing was previously used on SCHEDULED_JOBS_INDEX but is optional (not _routing.required: true), so SDK migration works without routing support
• Depends on Use SdkClient for persistence in IndexAlertingComment, IndexMonitor #2081 for SdkUtils.kt

Related Issues

Part of #2094

Part of #2094

Check List

• New functionality includes testing.
• New functionality has been documented.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

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-of-origin).

[eirsep]

why aren't we adding it in the constructor?

[manaswini1920]

Because MonitorMetadataService is a Kotlin object (singleton), not a class — it doesn't have a constructor. It's initialized via MonitorMetadataService.initialize(client, clusterService, xContentRegistry, settings) which sets fields individually. The
sdkClient follows the same pattern.

You could add it as a parameter to initialize() instead of setting it separately. That would be cleaner:

kotlin

fun initialize(
    client: Client,
    clusterService: ClusterService,
    xContentRegistry: NamedXContentRegistry,
    settings: Settings,
    sdkClient: SdkClient
) {
    ...
    this.sdkClient = sdkClient
}

i can take it as follow up on the next PR

[eirsep]

isthis a common method used every where. can we move it to commons and add an extra log line

[manaswini1920]

ack