Misseditor: unable to load mission file.

you can click "Save WP File" - and save a mission.
But try to load a mission - "Load WP File" - it will not throw an error, just "never" complete.
Please try with :
[wp.txt](https://github.com/ArduPilot/MAVProxy/files/12999485/wp.txt)

This file is saved using Mavproxy Misseditor - and works fine with "wp load wp.txt"

Start in the Misseditor workflow by reproducing the issue with the attached wp.txt file and comparing it with the working `wp load wp.txt` command. Trace the "Load WP File" action until it stops completing; done means the provided mission loads successfully without an error or indefinite wait.

Written by the indexing model from the issue text.