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]

Is there anybody reviewing that PR?

[epugh]

I had started a review, and never finished it!

[epugh]

I tried to push latest main updates to the branch, but i don't have permissions to push to your branch... Could you update and add a CHANGES.txt entry? Using the "via Eric Pugh" style and then I'll merge and back port.

[epugh]

@ds-manzinger I just went to merge, and of course my old enemy, CHANGES.txt has merge conflict. Would you mine fixing that and then I'll click the merge button! Lookign forward to getting this in.