HDDS-16131. Intermittent failure in TestBlockDeletingService#testBlockDeletionMetricsUpdatedProperlyAfterEachExecution

[echonesis]

What changes were proposed in this pull request?

This patch ensures that BlockDeletingServiceTestImpl is shut down in a finally block. Service shutdown waits for the deletion tasks to finish and release their container DB references before test cleanup runs.

The same lifecycle handling is also added to testChecksumFileUpdatedWhenDeleteRetried, which starts the service without shutting it down and is susceptible to the same teardown race.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-16131

How was this patch tested?

Local Test

mvn -pl :hdds-container-service test \
    -Dtest='TestBlockDeletingService#testBlockDeletionMetricsUpdatedProperlyAfterEachExecution+testChecksumFileUpdatedWhenDeleteRetried' \
    -DskipShade -DskipRecon -DskipDocs

GitHub Actions CI

• build-branch: https://github.com/echonesis/ozone/actions/runs/31658338732
• flaky-test-check: https://github.com/echonesis/ozone/actions/runs/31658570932