If a review request contains multiple comments of different types but

with the same IDs (such as a General Comment and a Diff Comment both

with ID 2), closing one of the comments would result in the other

comment appearing to close as well. In fact, the comment did not close,

it merely appeared to.
This was due to a bad check in CommentIssueBarView. It listened for

state updates and assumed that if the IDs matched, that was good enough.

It also needed to consider the comment type.
In order to do that, we first needed a way to represent the types. We

had hard-coded strings like 'diff_comments', but nothing formal, and

no way to get to it from the event handler.
There's now a CommentIssueManager.CommentTypes mapping of type

constants to values. The appropriate value is determined and then

provided when triggering issueStatusChanged. This allows the event

handler to perform the proper match.
Unit tests have been updated to check this for each supported comment

type.
In the future, we'll want to consider rethinking some of the way this

works, moving toward a model where we work directly with the comment

objects (ensuring there's only one object per comment) rather than

a more broad listener approach (which requires each handler to

perform these checks).

Unit tests pass.
Reproduced the original problem in a new database, and verified that

this fixes the state and UI collision.