Upstreaming from https://phabricator.wikimedia.org/T338306

Steps to reproduce:

1. As an admin, go to a task which has comments and to which you are not subscribed.
2. Click the dropdown for the comment, select Remove comment.

Actual outcome:
You got subscribed to the task.

Expected outcome:
You do not get subscribed to the task.
While adding a comment implies future discussion and interaction (thus it's likely that you should get subscribed), one-time cleanup intervention (removing) does not generally imply that you are interested in receiving future notifications about the task.
If there was for some reason a likeliness of another future intervention you could still subscribe yourself manually, however spammers are unlikely to target the same task again ({citation needed}).

Other comments:
Any (trans)action that concerns a comment (add, edit, remove) is currently handled in the same way.