🐛 Bug Report

When one of the cubes involved in regridding has coordinates with a geostationary coordinate system, their units ought to be in radians, however iris insists that they ought to be in meters and regridding will fail when it gets to this line:

This logic should be changed to allow for gesostationary coordinates with radian units.

See Proj for a description of the geostationary projection: https://proj.org/en/9.3/operations/projections/geos.html