Feature Request: Landing Gear button

I currently use my channels 6-8 for control of a gimbal and other functions and do not have access to a channel for landing gear control. I would be great if mission planner could have a button to retract and deploy the landing gear.

The issue names no files, tests, or entry points. Start by locating Mission Planner’s existing gimbal or control-channel UI and the landing-gear command handling, then confirm how a button can request retraction or deployment. Done means users can operate landing gear from a visible button without sacrificing channels 6–8 control.

Written by the indexing model from the issue text.