🐛 Fixed sticky "unsaved settings" modal
🐛 Fixed sticky "unsaved settings" modal

fixes https://github.com/TryGhost/Team/issues/777

- the unsaved settings modal would come back if you left a settings
  sub-page with unsaved changes and then came back to the page
- if you then clicked on "Leave", Admin would crash with a Sentry error
  of `Cannot read property 'finally' of undefined`
- we had a similar bug in
  https://github.com/TryGhost/Admin/commit/e73920eee83726081f8dede34e16284d97fa8ea4
  and the fix was to remove the `.finally` because it assumed the
  confirm action returned a promise
- this commit performs a similar fix and seems to resolve the problem

TryGhost/Ghost-Admin,TryGhost/Ghost-Admin