Flag Submission box does not disappear until full page reload

[rbclark]

Currently when a user submits a flag the Flag Submission box still displays until page reload.

The desired behavior is as follows:

• Admins can submit the same flag over and over and it should never create a solved challenge, and therefore they will only be shown the text saying "Flag Accepted" but after page reload they will be able to submit again.
• Players should only be able to submit a flag once, and once they see "Flag Accepted" they should not have the option to resubmit.

Tests to verify this behavior would be awesome, since admins are unable to verify it by hand without creating a team account.

[camdenmoors]

Should be fixed with Sean's #532

[sesheikholeslam]

Should be fixed with Sean's #532

Unfortunately I think the fix I made in that PR makes the flag submission box disappear when the user submits both a correct and incorrect flag.