GUI template in GUI repository does not make sense because all issues created in this repo should be related to GUI. bitcoin/bitcoin has link for GUI repo in issue templates.
Before this PR:

After this PR:

GUI template in GUI repository does not make sense because all issues created in this repo should be related to GUI. bitcoin/bitcoin has link for GUI repo in issue templates.
Before this PR:

After this PR:

This is a monotree. It is not possible to modify one repo, but not the other. Please submit your pull request to the main repo.