fix Annotation deletion

[naknomum]

Annotations which have MatchResults and/or Embeddings cannot be deleted without first resolving these foreign-key constrained objects

PR fixes #1562

• ann.deleteMatchResults() and ann.deleteEmbeddings() created
• ann.prepareForDeletion() helper method to combine above methods with other pre-delete functionality (e.g. remove from Tasks, etc)
• insert above methods where needed in servlets and api code
• jdo tweak to make MatchResultProspects dependent on MatchResults (for deletion cascade)
• front end changes to progress spinner during deletion

Note: also contains a couple bug fixes, one related, another not so much:

• numberProspects as property on MatchResult so the we can max out number we actually store on the object; this is to prevent 10s of thousands(!) of prospects being stored in the db, which rendered deletion much too slow and ate up unnecessary db/disk
• small but powerful SiteSettings bug that accidentally disabled vector/embedding search

[codecov-commenter]

Codecov Report

❌ Patch coverage is 67.44186% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 51.61%. Comparing base (af0abd3) to head (0a7d4fe).

Files with missing lines	Patch %	Lines
frontend/src/pages/BulkImport/BulkImportTask.jsx	50.00%	12 Missing ⚠️
...pages/MatchResultsPage/stores/matchResultsStore.js	88.23%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1563      +/-   ##
==========================================
+ Coverage   51.54%   51.61%   +0.07%     
==========================================
  Files         308      308              
  Lines       11952    11976      +24     
  Branches     3833     3736      -97     
==========================================
+ Hits         6161     6182      +21     
- Misses       5510     5514       +4     
+ Partials      281      280       -1     

Flag	Coverage Δ
backend	51.61% <67.44%> (+0.07%)	⬆️
frontend	51.61% <67.44%> (+0.07%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.