Need to display critical errors

ArduPilot sends critical internal errors on things that should never happen. A count of the errors is in SYS_STATUS.errors_count4. The bitmask of what errors have happened is in errors_count1 and errors_count2 (16 bits each).
It is important that we get logs from users when this happens so we can find and fix the cause

Start by locating where Mission Planner handles the ArduPilot SYS_STATUS message and displays its fields. The issue identifies errors_count4 as the error count and errors_count1/errors_count2 as the 32-bit error bitmask; clarify the intended display and log behavior before starting, since the issue does not specify either.

Written by the indexing model from the issue text.