[Feature Flag] - Remove enable_fix_for_pnpm_no_change_error Feature Flag

[kbukum1]

What are you trying to accomplish?

This change removes the enable_fix_for_pnpm_no_change_error feature flag from dependabot-core and dependabot-api, making the logic always behave as if the flag were enabled. This simplifies the code and ensures the fix is always applied.

What issues does this affect or fix?

The feature flag is no longer needed as the fix is stable, and removing it helps streamline the codebase.

Anything you want to highlight for special attention from reviewers?

• The removal of the feature flag is straightforward, but please review to ensure no unintended dependencies remain.
• All conditional checks for this flag have been removed or modified to assume it is always true.

How will you know you've accomplished your goal?

• All related tests should pass without issues.
• The expected behavior (previously gated by the feature flag) should now be the default behavior.
• Code should be simpler and easier to maintain without feature flag conditionals.

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.

[kbukum1]

Review Tip: We were using dependencies_with_prioritization as dependencies method when enable_fix_for_pnpm_no_change_error was enabled.