Revert "Use auth code flow (#3398)"

[byronkarlen]

Why

This reverts commit 1604b7b. (PR #3398)

eas login --sso is broken.

How

How did you build this feature or fix this bug and why?

Test Plan

Ran eas login -sso successfully against staging. Used the uuid suffix with stub-idp to avoid signup flow.

[github-actions]

Subscribed to pull request

File Patterns	Mentions
**/*	@douglowder

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[github-actions]

✅ Thank you for adding the changelog entry!

[codecov]

Codecov Report

❌ Patch coverage is 25.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 52.58%. Comparing base (0dcd6d4) to head (f423078).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...es/eas-cli/src/user/expoBrowserAuthFlowLauncher.ts	25.00%	5 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3422      +/-   ##
==========================================
+ Coverage   52.54%   52.58%   +0.04%     
==========================================
  Files         806      806              
  Lines       33621    33592      -29     
  Branches     6986     6983       -3     
==========================================
- Hits        17664    17662       -2     
+ Misses      14571    14546      -25     
+ Partials     1386     1384       -2     

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