forms: oops: Properly validate forms for agents

This patch fixes a small glitch where validation might be bypassed for
fields for agents. Previously there was a glitch where required fields would
have their validation errors ignored.
Merge pull request #1369 from greezybacon/issue/form-validation-agents

forms: oops: Properly validate forms for agents

Reviewed-By: Peter Rotich <peter@osticket.com>