R1:d2e1dd0ef092

In Applications, always redirect back to the detail page after edits

Summary:
Ref T12685. When you edit an application's policies but don't make any changes, you currently get stuck on the same page. This isn't how other edit screens work, and I think it's a holdover from eras long ago.

Make it consistent with other applications.

Also, fix a missing `pht()`.

Test Plan:
- Edited an application configuation.
- Clicked "Save" without making changes.
- After patch, was redirected back to detail page…