[Sorbet] Add strict typing for logger formats

[markhallen]

What are you trying to accomplish?

This PR adds strict typing to the logger formats Dependabot::Logger::BasicFormatter and Dependabot::Logger::JobFormatter.

How will you know you've accomplished your goal?

• The code has been refactored to be type-safe with Sorbet, eliminating reliance on unsafe casts.
• The functionality should remain unchanged.

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.