SOLR-17306: fix replication problem on follower restart

[ds-manzinger]

https://issues.apache.org/jira/browse/SOLR-17306

Same as #2873 -> but now against main branch

Description

If Leader has Replication disabled - do not delete Followers data on restart

Solution

Check if Leader Replication is enabled

Tests

Implemented Unit Tests, that check different restart scenarios. Enable Directory Storage for Replica, othwerwise tests will not work because memory is cleaned on restart

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended, not available for branches on forks living under an organisation)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide

[ds-manzinger]

@epugh Sorry for that new Pull Request. Sync with apache/solr broke my history

PR was automatically closed 😢

[epugh]

waiting for checks to complete and then will merge! let's hope my nemesis CHANGES.txt doesn't get me!