Check out notification about editing comment, when user subscribes to topic and suitable branch with checked 'Auto subscribe'

Pre-Conditions:

1. User1 and User2 are registered and logged in
2. At least one branch is created
3. User2 has checked "Auto subscribe" checkbox in the profile
4. User1 has permissions CREATE_POSTS, VIEW_POSTS, EDIT_OTHERS_POSTS
5. User2 has permissions VIEW_POSTS, CREATE_POSTS
6. User1 created a topic.