Camera Gimbal setup screen should not change CAM_TRIGG_TYPE

If I set up a camera trigger with CAM_TRIGG_TYPE of "1", relay, any access to the Camera Gimbal setup page will change CAM_TRIGG_TYPE to "0", which effectively disable the camera. This happens even if there are no changes made on the page.
I suggest adding another data entry field on the Camera Gimbal setup page to select the camera trigger type rather than just arbitrarily changing it to "0".

Start by locating the Camera Gimbal setup page and tracing where CAM_TRIGG_TYPE is written when the page is opened; compare behavior with values "1" (relay) and "0". Done means opening the page without edits preserves the existing value and provides a way to select the trigger type, with regression coverage if relevant tests exist.

Written by the indexing model from the issue text.