Ctrl-F Toggle Safety Switch should be two separate buttons

We've had at least one user crash caused by the user "toggling" the safety switch and losing control of the vehicle when they wanted to enable movement of the servos (e.g. safety switch disabled?).

To make it safer we should replace the toggle with two buttons.

We should also check that the button specifies the target system id of the vehicle selected in the Connect drop-down on the main screen.

Related issue https://github.com/ArduPilot/MissionPlanner/issues/3124

Start by locating the Ctrl-F safety-switch control and tracing the selected vehicle from the Connect drop-down. Review related issue 3124, then verify the two-button behavior and the target system ID used for the selected vehicle; done means the toggle is replaced without allowing an ambiguous safety action.

Written by the indexing model from the issue text.