Resolve "do not set updated_at when creating note"

What does this MR do?

Using the Notes API, if created_at is supplied upon creation of the issue note, the updated_at will be updated as well to the current time. This leads to show that the note has been just edited even if the said note is said to be created some time ago.

This MR fixes that by making the updated_at the same as the created_at if that said field is supplied.

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

Why was this MR needed?

Fixes #46930 (closed)

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conform by the merge request performance guides
• Conform by the style guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #46930 (closed)