* use the same paging for "myChallenges" only loads 10 per call
* challenges: show loading above the load-more button (instead at the top)
* purple loading message and flat load-more button
* remove comment
* show loadMore button only when the request has 10 entries
* challenge card ui
* fix(various): correct issues from PRs rollout
1. Send Gems modal opens from profiles again
2. Contributor titles appear on hover again
3. Tags dropdown in tasks appears again
4. Only user's own @mentions get highlighted again
* fix(test): correct order of css classes in expect