Add smarter UI for form errors
Summary: Just makes the UI cleaner on full width or dialog forms (and mobile)
Test Plan:
run into a bunch of errors, test mobile breakpoints.
{F281585}
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Differential Revision: https://secure.phabricator.com/D11638