Fix cancel button in issue template update warning

What does this MR do?

Fixes not working Close button in issue template override warning.

This feature introduced in !16865 (merged) and related to issue #16188 (closed)

Note to maintainer: for the changes/additions please see the threads I created in the MR diff.

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

Mentions #16188 (closed)