Make extract_point/extract_location/extract_coordinate_points preprocessor functions lazy #2446
Description
These preprocessor functions depend on interpolation schemes in Iris:
ESMValCore/esmvalcore/preprocessor/_regrid.py
Lines 75 to 79 in d37a502
which are not lazy:
https://github.com/SciTools/iris/blob/57096f29f6f2c5ff278d616df5e2da4d2bab95e2/lib/iris/analysis/_interpolation.py#L208-L209