fix(auth): fix credential decoding

[harsh62]

Issue #

#3937

Description

The issue fixes the error that is caused when the auth flow type doesn't have the correct type. The idea is to catch the decoding error and use the legacy container to decode the flow type.

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

Attention: Patch coverage is 20.75472% with 42 lines in your changes missing coverage. Please review.

Project coverage is 67.65%. Comparing base (06207f4) to head (426cf99).

Files with missing lines	Patch %	Lines
...ces/AWSCognitoAuthPlugin/Models/AuthFlowType.swift	22.44%	38 Missing ⚠️
...dentialStorage/AWSCognitoAuthCredentialStore.swift	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3938      +/-   ##
==========================================
- Coverage   67.70%   67.65%   -0.06%     
==========================================
  Files        1125     1125              
  Lines       52075    52114      +39     
==========================================
  Hits        35256    35256              
- Misses      16819    16858      +39     

Flag	Coverage Δ
API_plugin_unit_test	70.37% <ø> (+0.04%)	⬆️
AWSPluginsCore	70.36% <ø> (ø)
Amplify	47.89% <ø> (ø)
Analytics_plugin_unit_test	85.20% <ø> (ø)
Auth_plugin_unit_test	73.25% <20.75%> (-0.19%)	⬇️
DataStore_plugin_unit_test	83.41% <ø> (-0.02%)	⬇️
Geo_plugin_unit_test	74.86% <ø> (ø)
Logging_plugin_unit_test	63.11% <ø> (ø)
Predictions_plugin_unit_test	35.49% <ø> (ø)
PushNotifications_plugin_unit_test	88.43% <ø> (ø)
Storage_plugin_unit_test	76.88% <ø> (ø)
unit_tests	67.65% <20.75%> (-0.06%)	⬇️

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