TT-4464: fix parsing of events exception error

[googsvg]

Summary

• Fix JsonDataException crash when Nylas API returns an unrecognized conferencing provider (e.g. "Hangouts"). Unrecognized values now deserialize to null instead of throwing.
• Applied the same fix to CreateEventAutoConferencingProvider and CreateEventManualConferencingProvider for consistency.
• Expose url, originalErrorMessage, and timeout as readable properties on NylasSdkRemoteClosedError / NylasSdkTimeoutError.
• Fix deprecated RequestBody.create() calls; suppress legitimate Moshi adapter warnings (UNUSED_PARAMETER, UNCHECKED_CAST).

Closes #265

License

I confirm that this contribution is made under the terms of the MIT license and that I have the authority necessary to make this contribution on behalf of its copyright owner.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.49%. Comparing base (fd75345) to head (d953a36).

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #320      +/-   ##
============================================
+ Coverage     82.44%   82.49%   +0.05%     
  Complexity      358      358              
============================================
  Files            38       38              
  Lines          1031     1034       +3     
  Branches         95       95              
============================================
+ Hits            850      853       +3     
  Misses          122      122              
  Partials         59       59              

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