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Compatibility, Deprecation, and Migration Plan

1. We will add a deprecated annotation on `AssignmentsManager#QUEUED_REPLICA_TO_DIR_ASSIGNMENTS_METRIC`.
2. Add new `AssignmentsManager#QUEUED_REPLICA_TO_DIR_ASSIGNMENTS_METRIC_NAME` which `metricName` is `kafka.server:type=AssignmentsManager`  and add it to `AssignmentsManager#metricsRegistry`.
3. Delete `AssignmentsManager#QUEUED_REPLICA_TO_DIR_ASSIGNMENTS_METRIC` at the next major release and remove it from `AssignmentsManager#metricsRegistry`Add new warn log which is "org.apache.kafka.server:type=AssignmentsManager will be deprecated in the future, it will rename to kafka.server:type=AssignmentsManager"in `AssignmentsManager#metricName` method.In the next major release, we will update `AssignmentsManager#metricName` method to return `kafka.server:type=AssignmentsManager`.

Test Plan

n/a

Rejected Alternatives

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