Allow exit from credentials command

[douglowder]

Why

The command eas credentials does not provide a way to exit other than control-C, if no platform flag is passed in.

How

Add an "Exit" choice to the platform prompt.

Test Plan

Tested locally.

[douglowder]

• Allow exit from credentials command #3269 👈 (View in Graphite)
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

Size Change: +3.86 kB (+0.01%)

Total Size: 54.9 MB

Filename	Size	Change
./packages/eas-cli/dist/eas-linux-x64.tar.gz	54.9 MB	+3.86 kB (+0.01%)

_{compressed-size-action}

[codecov]

Codecov Report

❌ Patch coverage is 31.25000% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 51.89%. Comparing base (4476c87) to head (80f2490).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/eas-cli/src/platform.ts	28.58%	8 Missing and 2 partials ⚠️
.../eas-cli/src/credentials/manager/SelectPlatform.ts	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3269      +/-   ##
==========================================
- Coverage   51.90%   51.89%   -0.00%     
==========================================
  Files         632      632              
  Lines       25874    25886      +12     
  Branches     5438     5440       +2     
==========================================
+ Hits        13427    13431       +4     
- Misses      11327    11333       +6     
- Partials     1120     1122       +2     

☔ 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.

[github-actions]

⏩ The changelog entry check has been skipped since the "no changelog" label is present.