Add client-level MetricPublisher support to the S3 CRT client

[jencymaryjoseph]

Motivation and Context

The S3 CRT-based client (S3AsyncClient.crtBuilder()) currently has no MetricPublisher support - unlike the
standard client, there's no way to collect metrics from it. CRT already emits per-request telemetry
(S3RequestMetrics, via the onTelemetry callback added in aws-crt-java#928); this change wires it to the SDK's MetricPublisher API for publishers configured on the builder (client level). Request-level and copyObject support will follow separately.

Modifications

• Add metricPublishers(Collection<MetricPublisher>) and addMetricPublisher(MetricPublisher) to
  S3CrtAsyncClientBuilder.
• Route these publishers to the CRT transport only (never the inner delegate client), so the inner pipeline
  stays a no-op and no empty ApiCall is emitted — all metrics come from CRT telemetry.
• S3CrtResponseHandlerAdapter.onTelemetry(...) publishes each underlying CRT request as its own ApiCall → ApiCallAttempt → HttpClient collection (ServiceId, OperationName, ApiCallSuccessful, RetryCount,
  durations, request IDs, HttpClientName=s3crt); a fanned-out transfer (e.g. a multipart getObject) publishes
  one collection per underlying request.
• Carry the publishers to the adapter via a new internal METRIC_PUBLISHERS execution attribute; unavailable
  metrics are skipped per-metric and onTelemetry never throws back into the native callback.

Follow-ups will add request-level publisher overrides, copyObject parity, expanded integration tests, and
more metrics as CRT exposes them (HTTP status- aws-crt-java#1011, endpoint URL, TTFB/TTLB,
connection-pool).

Testing

• Unit (S3CrtResponseHandlerAdapterMetricsTest): mapping correctness, unavailable-metric skip, failed
  attempt (ApiCallSuccessful=false), empty-publisher no-op, N callbacks → N collections, and retry (per-attempt
  collections with increasing RetryCount). S3CrtResponseHandlerAdapterTest updated for the new constructor.
• Integration (S3CrtClientMetricPublisherIntegrationTest): single-part getObject, multipart getObject
  (fan-out), putObject, and a failed getObject, verifying the published collections (ServiceId=S3,
  non-zero ApiCallDuration, HttpClientName=s3crt).

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed
• I have added a changelog entry. Adding a new entry must be accomplished by running the scripts/new-change script and following the instructions. Commit the new file created by the script in .changes/next-release with your changes.
• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license

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