Upgrade solr from 9.2 to 9.9

[mabdellatif88]

Changes in this PR

• Upgrading solr config in the repo CI (GitHub action unit-tests.yml) from 9.2 to 9.9
• Removing the deprecated use of lib directives from the repo's solr config file solrconf/conf/solrconfig.xml
• Importing the needed solr modules in GitHub action unit-tests.yml by another way that is supported and encouraged by solr starting 9.9 onwards

Reviewer Checklist

• All JavaScript tests pass
• All Python tests pass
• All 12 automated checks pass
• The application (including the search function) works as expected locally and in staging

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.73%. Comparing base (4d0e318) to head (5f2cc95).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #776      +/-   ##
===========================================
- Coverage    94.73%   94.73%   -0.01%     
===========================================
  Files          140      140              
  Lines         8553     8542      -11     
  Branches         7        8       +1     
===========================================
- Hits          8103     8092      -11     
  Misses         450      450              

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