Fix bug where default values were not being used in GitHub Action runners when environmental variables are not set. Now, if an environmental variable cannot be found and no default is given, the default value will be used if one exists. This will prevent errors during setup on different environments and ensure system stability.
A new function `get_setting_or_env` was implemented to facilitate fetching of either settings or environmental variables in the GitHub Action Runner. This was necessary to resolve an issue where a certain undefined behaviour occurs in GitHub Actions, leading to an attribute error. The new function also provides a default value parameter to ensure the return of a value even in failed attempts to fetch from either settings or environment variables.
A utility function (`is_true`) was added to take care of validating and converting boolean values from string or boolean types. This function is used in three parts of the `run_action` method where automatic PR review, description, and improvement actions are triggered based on environment settings. This change makes the condition checks cleaner and prevents code duplication.
