HDDS-15492. Support OM follower read for gRPC client

[echonesis]

What changes were proposed in this pull request?

This PR adds OM follower read support for the gRPC OM transport.

Before this change, OM follower read support was available through the Hadoop RPC transport path, but gRPC clients still used the leader-oriented path for OM requests. This PR extends GrpcOmTransport so follower-read eligible OM requests can be sent to follower OM nodes when follower read is enabled.

The change includes:

• Applying the configured default read consistency hint for gRPC OM requests.
• Routing follower-read eligible read requests to non-leader OM nodes.
• Falling back to the leader path when follower read cannot be served by a follower.
• Reusing OM failover exception handling for follower read failures.
• Configuring per-OM gRPC ports in the HA mini cluster.
• Adding unit and integration coverage for gRPC follower read behavior.

Generated-by: OpenAI Codex

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-15492

How was this patch tested?

Tested with:

mvn clean test -pl :ozone-common,:ozone-integration-test -am \
  -Dtest=TestS3GrpcOmTransport,TestOzoneManagerHAWithAllRunning,TestOzoneManagerHAWithStoppedNodes,TestOzoneManagerHAFollowerReadWithAllRunning,TestOzoneManagerHAFollowerReadWithStoppedNodes,TestOzoneManagerPrepare \
  -DskipShade -DskipRecon -DskipDocs

GitHub Actions CI: https://github.com/echonesis/ozone/actions/runs/28155889076

[ivandika3]

Thanks @echonesis , just saw it briefly, left one comment about the test. Will review more later.

[ivandika3]

Thanks @echonesis , overall LGTM. Just left a few comments.

It'll be good if you can test this on your cluster after this is merged.

[ivandika3]

@echonesis Thanks for the update. LGTM +1.