GitAuto: Add unit tests to services/github/actions_manager.py

[gitauto-for-dev]

Resolves #437

What is the feature

Add unit tests to services/github/actions_manager.py to enhance code reliability and maintainability.

Where / How to implement the feature and why

Create a new test file tests/services/github/test_actions_manager.py and implement comprehensive unit tests covering all functions and classes within actions_manager.py. Utilize pytest along with unittest.mock to mock external dependencies, ensuring tests are isolated and do not rely on external systems. This approach follows modern best practices for testing in Python, ensuring that the actions_manager functionalities behave as expected and facilitating easier future modifications.

Anything the issuer needs to do

No action required.

Test these changes locally

git fetch origin
git checkout gitauto-wes/issue-437-20241222-225936
git pull origin gitauto-wes/issue-437-20241222-225936