Remove mark unsafe button
Remove mark unsafe button

Summary:
The button is broken now because it's sending the build tags in the wrong place.
Since nothing makes use of the unsafe tag, remove the button.

Test Plan: To be tested locally by verifying button doesn't show up anymore.

Reviewers: kylec

Reviewed By: kylec

Subscribers: changesbot, dgoldstein

Tags: #changes_ui

Differential Revision: https://tails.corp.dropbox.com/D223984

dropbox/changes,dropbox/changes,dropbox/changes,dropbox/changes