FIX: Unassign label sometimes touches avatar

[AndrewPrigorshnev]

We've noticed that sometimes it looks like this:

Turned out that happens when a topic has several assignments and those contain assignments to users and to groups. We don't show avatars for groups, but the code sees there are several assignees and applies overlapping styling.

I corrected the logic, and that fixed the issue.

Here is how avatars on this button behave. If there are from one to many assignments on the topic, but all the assignees are groups, we don't show avatars, only label:

If there are from one to many assignments to the same user we show the avatar of that user (and even if there are also assignments to groups there is no overlapping):

And if there are from two to many assignments to different users, we show avatars of first two users:

[pmusaraj]

Very nice, thanks!