### Is there an existing issue or pull request for this? - [x] I have searched the existing issues and pull requests ### Feature description When ExpressLRS is the RC protocol, RC5 MUST be used to arm (or at the very least, set high upon arming ### Desired solution Do it automatically if ExpressLRS is the RC protocol And also tell the user that FLTMODE_CH must be != 5 ### Alternatives considered Reading the documentation ### Additional context This was originaly reported by @yuri-rage on this post: https://discuss.ardupilot.org/t/pixhawk-quadcopter-tipping-on-takeoff/137067/50