Issue title: userlock icon should appear in hover state for popup menu entries
 Issue body: this should be some simple CSS property herding.

 Comments: 
 Comment 0: we are no longer using the lock icon but a privacy badger icon that shows up when a domain is taken over manually that can be clicked to return control of the domain to privacy badger.

{'source': 'GithubIssues', 'repo_name_with_owner': 'EFForg/privacybadger', 'issue_id': 22161034, 'repo_stars': 2598.0}