Enable `check_maven_path_first` by default

🏆 Context

In %13.12, we introduced and enabled a feature flag that improves the logic in the maven package registry when it deals with package file requests that doesn't exist.

To get the full context, see the MR that introduced the feature flag : !59241 (merged)

Rollout issue: #327487 (closed)

🔬 What does this MR do?

• Enable check_maven_path_first by default
• Add a changelog entry
• No documentation is needed because it's a ~performance improvement. No feature was changed.

📹 Screenshots (strongly suggested)

n / a

📏 Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because _____.
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team