Process up to 100 commit messages for references when pushing to a new default branch

What does this MR do?

Patch for the bug described in #56683 (closed). On first push to the default branch, we are currently not processing commits for references to issues. This is done on purpose, probably for performance reasons, to avoid processing thousands of commits. If we limit the commit processing to a reasonable number of commits, performance will not be impacted significantly, and this will cease to appear as a bug for the vast majority of users.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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

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