Make cubes with different coordinate systems work with extract_location

[nhsavage]

Description

When using CORDEX data on a model with a rotated pole grid with the extract_location pre-processor it fails with:

ValueError: Interpolation coords must be 1-d for rectilinear interpolation.

This branch extends the function: extract_point in preprocessor/_regrid.py
to cope with cases where the dimension coordinates are not latitude and longitude

Closes #2177

TO DO:

• add suitable integration and unit tests for the new functionality
• rebase once changes to unit testing made by Emma Hogan are on main Remove mocking from tests in tests/unit/preprocessor/_regrid/test_extract_point.py #2193
• some changes to documentation will be needed - the dimensions are different if the cube is not in latitude and longitude because there is no longer a 1:1 mapping of the scalar coordinate to a single value in either x or y

Link to documentation:

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[codecov]

Codecov Report

Merging #2186 (64e5e76) into main (4fd8701) will decrease coverage by 0.10%.
Report is 10 commits behind head on main.
The diff coverage is 35.00%.

❗ Current head 64e5e76 differs from pull request most recent head 5f254f7. Consider uploading reports for the commit 5f254f7 to get more accurate results

@@            Coverage Diff             @@
##             main    #2186      +/-   ##
==========================================
- Coverage   93.10%   93.01%   -0.10%     
==========================================
  Files         237      237              
  Lines       12826    12845      +19     
==========================================
+ Hits        11942    11948       +6     
- Misses        884      897      +13     

Files	Coverage Δ
esmvalcore/preprocessor/_regrid.py	94.76% <35.00%> (-3.49%)	⬇️