Sign error in ellipsoid height calculation

[makeller1]

Bug report

Issue details
Seeing a sign error on how the ellipsoid height is calculated.
The undulation is subtracted from alt here
height_elipsoid_mm = loc.alt*10 - undulation*1000;

Which doesn't make sense considering the alt is calculated as height - undulation
state.location.alt = (int32_t)(((float)temp.Height - temp.Undulation) * 1e2f);

That would imply ellipsoid height = height - 2 * undulation.

@hendjoshsr71

Version
Master

Platform
[X] All
[ ] AntennaTracker
[ ] Copter
[ ] Plane
[ ] Rover
[ ] Submarine

[rmackay9]

This is probably one for @tridge, @hendjoshsr71 and/or @BluemarkInnovations to look into as the code was added in PR #21075

[makeller1]

Addressed by PR #23942.

[tridge]

thanks! fixed with your PR