Change from hwvoltage to boardvoltage


This flight code PR https://github.com/ArduPilot/ardupilot/pull/21707 removes the automatic send of the "hwvoltage" value (the nicely scaled one) forcing the GCS to rely on the "boardvoltage" value which is scaled in millivolts. It might be a good idea for MP to scale this value to volts (divide by 1000) before displaying it to make it more user friendly.

By the way, the flight code change will be included in 4.4.

Start by locating Mission Planner’s display handling for the "boardvoltage" value and compare its behavior with the linked ArduPilot flight-code PR 21707. Verify how the millivolt value is shown, then confirm that the completed change displays it as volts and remains compatible with the flight-code change planned for 4.4.

Written by the indexing model from the issue text.