feat: expose more metrics for S3

[azkrishpy]

Issue #, if available:

Description of changes:
Adds/fixes S3 request telemetry exposed via S3RequestMetrics:

• getServiceId() — now returns "S3" (was "s3"), matching SDK convention
• getServiceEndpoint() — now returns a full scheme-qualified URL (e.g. https://bucket.s3.region.amazonaws.com) instead of a bare host, so it can be parsed with URI.create()
• getTimeToFirstByte() / getTimeToLastByte() — now return durations (delta from request start), not raw timestamps
• getConnectionAcquisitionDurationNs() — new, time spent acquiring a connection for the request
• getHttpManagerMetrics() — new, snapshot of the endpoint's connection pool state (available/pending/leased concurrency) taken just before this request asks for a connection
• S3Client.getMaxActiveConnections() — new, the connection concurrency cap of the client.
• Updates submodules to latest versions.

Requires awslabs/aws-c-s3#673 for newly bound client level API.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[DmitriyMusatkin]

description of changes? title of pr does not seem to match with whats in the diff?