Ctrl-F "Toggle Safety Switch" button should ask, "are you sure" if vehicle is armed

We've had this report on the flight code side regarding the button and we have several improvements we plan to make ([see PR](https://github.com/ArduPilot/ardupilot/pull/22051)) but we think it would also be good to change MP in one of these ways:

- Add an "Are You Sure?" question OR
- Replace the single button with "Armed" and "Disarmed" or "Safety On", "Safety Off" buttons

Related issue https://github.com/ArduPilot/MissionPlanner/issues/2170

Start by locating the Ctrl-F "Toggle Safety Switch" button in Mission Planner and read the linked ArduPilot PR and related issue #2170 for context. Confirm which of the two proposed UI changes is wanted, then define done as preventing an unintended safety change while the vehicle is armed and covering the selected behavior with a test.

Written by the indexing model from the issue text.