Bugfix #63689330: Admin can not edit help

A few notes: `allow_help_edit` mustache helper is called two times when the help modal is opened. In the first call the `instance` variable is the help object, but in the second call it's undefined.

Moving the helper call out of the `{{#instance.content}}` check makes the instance variable be properly set in both calls, but I can't explain why this fixes the problem. It seems like a bug in the way helpers are handled.