Fix a transaction editor "continue;" inside "switch()" for PHP 7.3
Summary: See https://discourse.phabricator-community.org/t/new-git-commit-processing-fails-on-php-7-3/. This "continue" should be a "break".
Test Plan:
{F6045490}
- Tried to assign a task to myself while I was already the owner, got an appropriate error.
Reviewers: amckinley
Reviewed By: amckinley
Differential Revision: https://secure.phabricator.com/D19844