Fix an issue where inline comments with only edit suggestions are considered empty
Ref T13513. An inline is not considered empty if it has a suggestion, but some of the shared transaction code doesn't test for this properly.
Update the shared transaction code to be aware that application comments may have more complex emptiness rules.
- Posted an inline with only an edit suggestion, comment went through.
- Tried to post a normal empty comment, got an appropriate warning.
Maniphest Tasks: T13513
Differential Revision: https://secure.phabricator.com/D21287