feat(symbolication): get gcp token instead of credentials

[Litarnus]

This PR adds the GCP token fetching for symbolication to pass it down to symbolicator instead of using credentials.

[codecov]

Codecov Report

Attention: Patch coverage is 42.85714% with 4 lines in your changes missing coverage. Please review.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/sentry/lang/native/sources.py	33.33%	4 Missing ⚠️

❌ Your patch check has failed because the patch coverage (42.85%) is below the target coverage (50.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #91016       +/-   ##
===========================================
+ Coverage   46.15%   87.69%   +41.54%     
===========================================
  Files       10283    10299       +16     
  Lines      583526   584359      +833     
  Branches    22583    22583               
===========================================
+ Hits       269299   512445   +243146     
+ Misses     313797    71484   -242313     
  Partials      430      430