[eas-cli] use google service key detection in credentials service

[quinlanj]

Checklist

• I've added an entry to CHANGELOG.md if necessary.
• I've tagged the changelog entry with [EAS BUILD API] if it's a part of a breaking change to EAS Build API (only possible when updating @expo/eas-build-job package).

Why

The current logic in the Android submission service has some features that detect potential Google Service Jsons and suggest them to the user. I think this is a very good idea, so I've taken most of this logic, made minor adjustments to it, and put it in the credentials service.

This logic is copied over instead of refactored because in a followup PR, I'm thinking the submissions logic here can be changed to something like this:

 // path is explicitly passed in
 if (serviceAccountKeyPath) {
      return result({
        sourceType: ServiceAccountSourceType.path,
        path: serviceAccountKeyPath,
      });
    } 

 // fallback to credentials service otherwise
 if (keyIsSetupOnCredentialsService) {
    return savedKey;
 }

 return await (new SetupGoogleServiceAccountKey().runAsync(credentialsCtx));

Test Plan

• modified tests pass

[github-actions]

Size Change: +2.86 kB (0%)

Total Size: 22.4 MB

Filename	Size	Change
./packages/eas-cli/dist/eas-linux-x64.tar.gz	22.4 MB	+2.86 kB (0%)

_{compressed-size-action}

[codecov]

Codecov Report

Merging #660 (6a1be34) into main (e8d71a5) will increase coverage by 0.17%.
The diff coverage is 91.49%.

❗ Current head 6a1be34 differs from pull request most recent head 1ca6379. Consider uploading reports for the commit 1ca6379 to get more accurate results

@@            Coverage Diff             @@
##             main     #660      +/-   ##
==========================================
+ Coverage   49.37%   49.54%   +0.17%     
==========================================
  Files         314      314              
  Lines       10782    10822      +40     
  Branches     2030     2036       +6     
==========================================
+ Hits         5323     5361      +38     
- Misses       5453     5455       +2     
  Partials        6        6              

Impacted Files	Coverage Δ
...s/android/actions/CreateGoogleServiceAccountKey.ts	84.00% <75.00%> (-0.21%)	⬇️
...edentials/android/utils/googleServiceAccountKey.ts	86.77% <97.15%> (+10.30%)	⬆️

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[dsokal]

🚀