Use RemoveSafeDeltaCounterCell for PerWorker counters

[JayajP]

Dataflow Streaming harness's metrics container will store per worker counters in a new RemoveSafeDeltaCounterCell.

For the new PerWorkerMetrics we want to support dynamically creating metrics that may not live the lifetime of the job, therefore we need to implement garbage collection for stale metrics.

E.g. We want to support BigQuery Metrics on a per-bigquery-table basis. If the pipeline uses dynamic destinations to write to 100 tables at 12:00 and at 15:00 is only writing to a few tables, the underlying MetricsContainer should not hold on to metrics for all 100 tables.

InRemoveSafeDeltaCounterCell metric updates and deletions are handled atomically - using ConcurrentHashMap::compute and ConcurrentHashMap::remove respectively - ensuring safe garbage collection.

---

Thank you for your contribution! Follow this checklist to help us incorporate your contribution quickly and easily:

• Mention the appropriate issue in your description (for example: addresses #123), if applicable. This will automatically add a link to the pull request in the issue. If you would like the issue to automatically close on merging the pull request, comment fixes #<ISSUE NUMBER> instead.
• Update CHANGES.md with noteworthy changes.
• If this contribution is large, please file an Apache Individual Contributor License Agreement.

See the Contributor Guide for more tips on how to make review process smoother.

To check the build health, please visit https://github.com/apache/beam/blob/master/.test-infra/BUILD_STATUS.md

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI or the workflows README to see a list of phrases to trigger workflows.

[github-actions]

Assigning reviewers. If you would like to opt out of this review, comment assign to next reviewer:

R: @AnandInguva added as fallback since no labels match configuration

Available commands:

• stop reviewer notifications - opt out of the automated review tooling
• remind me after tests pass - tag the comment author after tests pass
• waiting on author - shift the attention set back to the author (any comment or push by the author will return the attention set to the reviewers)

The PR bot will only process comments in the main thread (not review comments).

[AnandInguva]

assign to next reviewer

[Abacn]

Thanks, left a few comments

[Abacn]

Java PreCommit failing test due to #28957 (comment)