[improve] Upgrade to zk 3.8.1

[dlg99]

Motivation

Upgrade to zk 3.8.1

Release notes: https://zookeeper.apache.org/doc/r3.8.1/releasenotes.html
Among other changes it includes improvement to "Reduce the performance impact of Prometheus metrics".

Modifications

ZK upgrade

Verifying this change

• Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

Matching PR in forked repository

PR in forked repository: dlg99#8

[hangc0276]

This PR should be cherry-picked to patch the release branch, so I removed the tag release/2.9.5 and release/2.10.4. This PR has been cherry-picked to branch-2.10, Please push another PR to revert this cherry-pick @liangyepianzhou. cc/ @codelipenghui

[codelipenghui]

@lhotari I noticed you have added release/2.9.5 release/2.10.4` labels, do you have any context about it? Just to make sure we will not miss critical fixes in the next release (2.10.5)