Use IID instead of ID for "Single issue" query

Most people don't know that there is a difference, furthermore you can't view the ID only the IID to the users on GitLab itself.

So it would be great to use IID instead of ID, e.g. user shall enter the issue ID after selecting the right project (so it is already unique and the right scope is available) and you can only search for it by getting all issues and iterate over all to find the right issue