New callbacks to standardise some dim names

[jwarner8]

Fixes #982
Also added new fix for pressure level coordinate where surface recipes actively seek cubes where there is no pressure level data, i.e. pressure level list = [], but some AIFS cubes have the pressure coordinate called 'pressure_level' so this ensures cubes use 'pressure'.

Contribution checklist

Aim to have all relevant checks ticked off before merging. See the developer's guide for more detail.

• Documentation has been updated to reflect change.
• New code has tests, and affected old tests have been updated.
• All tests and CI checks pass.
• Ensured the pull request title is descriptive.
• Conda lock files have been updated if dependencies have changed.
• Attributed any Generative AI, such as GitHub Copilot, used in this PR.
• Marked the PR as ready to review.

[github-actions]

[jwarner8]

Fixes additional bug in get_cube_yxcoordname, where a spatial coordinate could be returned even though the dimension is scalar, and not a dim_coord. And thus using get_cube_yxcoordname may suggest cube is spatial (even though its been collapsed and spatial coords still exist as scalars in the metadata).

[jwarner8]

Actually, hold fire, still not getting coverage for https://tmpweb.net/LXAHrJ43vmBu/z_f5ac9763053bfad5_read_py#t349. I will look tomorrow...

[jwarner8]

Now ready for review, I think I hadn't given the coverage time to update/might have been cached in browser, now back at 100% coverage.

[jfrost-mo]

A normalisation callback is a good idea.

The big think I notices was that you are converting to grid_latitude, where I think, looking at the CF Conventions, that we should be converting to latitude instead.

I'm also uncertain about whether we want to exclude scalar coordinates, as latitude and longitude are just as sensible on point data as they are on gridded.

[jwarner8]

Reviewed by James already and comments addressed, but not sure if I can merge until he approves. Adding @daflack as reviewer for final glance (and see if merges are possible if there is at least one reviewer who accepts)

[daflack]

Other than a typo looks good to me.

Have discussed this PR with JamesF in person Friday, and David has also re-reviewed so dismissing review as James on holiday for 3 weeks.