chore(auth): add unit tests and fix swift format

[harsh62]

Issue #

#3972

Description

General Checklist

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• All integration tests pass
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• New or updated tests include Given When Then inline code documentation and are named accordingly testThing_condition_expectation()
• If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.89%. Comparing base (ea874c1) to head (e7b8c80).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4120      +/-   ##
==========================================
+ Coverage   66.67%   66.89%   +0.21%     
==========================================
  Files        1129     1129              
  Lines       42616    42616              
==========================================
+ Hits        28415    28508      +93     
+ Misses      14201    14108      -93     

Flag	Coverage Δ
API_plugin_unit_test	68.41% <ø> (+0.02%)	⬆️
AWSPluginsCore	68.07% <ø> (ø)
Amplify	46.72% <ø> (ø)
Analytics_plugin_unit_test	84.84% <ø> (ø)
Auth_plugin_unit_test	72.52% <100.00%> (-0.04%)	⬇️
DataStore_plugin_unit_test	83.00% <ø> (+1.33%)	⬆️
Geo_plugin_unit_test	73.39% <ø> (ø)
Logging_plugin_unit_test	64.86% <100.00%> (ø)
Predictions_plugin_unit_test	33.89% <ø> (ø)
PushNotifications_plugin_unit_test	87.41% <ø> (ø)
Storage_plugin_unit_test	77.68% <ø> (ø)
unit_tests	66.89% <100.00%> (+0.21%)	⬆️

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