chore: Fixing retries in unit tests workflow

[ruisebas]

Description

Only setting test-without-building to true if there was a cache for the exact SHA that's being tested, or if there wasn't a main build cached.

Otherwise the retry would end up using an old successful build and result in a success, even if the actual tests in the current commit are not passing.

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-commenter]

Codecov Report

Merging #3293 (62548c7) into main (efc0061) will decrease coverage by 0.02%.
Report is 1 commits behind head on main.
The diff coverage is n/a.

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@@            Coverage Diff             @@
##             main    #3293      +/-   ##
==========================================
- Coverage   64.32%   64.31%   -0.02%     
==========================================
  Files        1075     1075              
  Lines       35880    35880              
==========================================
- Hits        23079    23075       -4     
- Misses      12801    12805       +4     

Flag	Coverage Δ
API_plugin_unit_test	67.07% <ø> (ø)
AWSPluginsCore	66.15% <ø> (ø)
Amplify	47.92% <ø> (+0.06%)	⬆️
Analytics_plugin_unit_test	81.37% <ø> (ø)
Auth_plugin_unit_test	74.00% <ø> (-0.09%)	⬇️
CoreMLPredictions_plugin_unit_test	59.44% <ø> (ø)
DataStore_plugin_unit_test	80.07% <ø> (+0.01%)	⬆️
Geo_plugin_unit_test	70.75% <ø> (ø)
Logging_plugin_unit_test	63.09% <ø> (ø)
Predictions_plugin_unit_test	37.29% <ø> (ø)
PushNotifications_plugin_unit_test	60.29% <ø> (ø)
Storage_plugin_unit_test	54.24% <ø> (ø)
unit_tests	64.31% <ø> (-0.02%)	⬇️

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see 7 files with indirect coverage changes

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