Handle large values on `MergeRequestDiffCommit` dates

What does this MR do?

Handle large values on MergeRequestDiffCommit dates

Are there points in the code the reviewer needs to double check?

No

Why was this MR needed?

When using abnormally large dates, the SQL insert would fail. This fix prevents that issue... at least until 2038...

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #39561 (closed)