Transforming Gfm also on paste so it works also in FF

What does this MR do?

This is an additional change so we have a fallback for Firefox and if the async call times out on other browsers during the copy event of GFM. It simply transforms the original HTML in an async way on paste if we don't have already transformed gfm.

What are the relevant issue numbers?

Closes #57561 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer