test: pytestify "tests/unittests/config/test_cc_timezone.py"

[MaheshG11]

Proposed Commit Message

test: pytestify "tests/unittests/config/test_cc_timezone.py"

Refactors the code in the file "tests/unittests/config/test_cc_timezone.py" 
using pytest. This helps remove dependance of this test on 
"tests/unittests/helpers.py:FileSystemMockingTestCase"

Fixes: part of GH-5760

Additional Context

This change removes the dependance of the test on FileSystemMockingTestCase and replaces it with fakefilesystem, a pytest fixture located in "tests/unittest/conftest".

Fixes: part of #5760

Test Steps

1. Run pytest tests/unittests/config/test_cc_timezone.py in main repository

Merge type

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number ([enhancement]: adapt unittests to pytest: drop use of FilesystemMocking testcases #5760)