[Announcements] Hide "disallow threaded replies" option when comments on Announcements have been disabled at the course level

[SamanthaOrcutt]

Problem statement:

When "Disable comments on announcements" is turned on at the course level settings, the option for "disallow threaded replies" is still visible to anyone with the ability to post announcements. Allowing threaded replies is not possible, since comments are already disabled.

Proposed solution:

When "Disable comments on announcements" is turned on at the course level settings, the option for "disallow threaded replies" will automatically hide/remove itself, since it is no longer applicable. This would clear out any nonfunctional options within the Announcement creation area.

User role(s):

admin,instructor,ta,designer