chore: Allow Android bindings to be built using local maven artefacts

[jamescrosswell]

This is just for contributors... when we need to debug issues in the Sentry SDK for Java/Android, it's useful to be able to build the .NET SDK using locally built versions of the Maven artefacts, to be able to quickly add logs and iterate etc.

This PR adds a UseLocalSentryMavenRepo build property that does just that.

#skip-changelog

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.85%. Comparing base (5dde625) to head (28f1485).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4873      +/-   ##
==========================================
- Coverage   73.86%   73.85%   -0.01%     
==========================================
  Files         483      483              
  Lines       17577    17577              
  Branches     3464     3464              
==========================================
- Hits        12983    12982       -1     
  Misses       3741     3741              
- Partials      853      854       +1     

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Cursor Bugbot has reviewed your changes and found 2 potential issues.

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[Flash0ver]

Got it to work on my machine.

Shall we add a brief instruction to CONTRIBUTING.md,
similar to https://github.com/getsentry/sentry-dotnet/pull/4551/changes#diff-eca12c0a30e25b4b46522ebf89465a03ba72a03f540796c979137931d8f92055?

[jamescrosswell]

Shall we add a brief instruction to CONTRIBUTING.md,

Done ✅