Harmonise variable names from UM Stash to LFRic variable and long_name

[ukmo-huw-lewis]

Adding variable name callback to make use of LFRic variable standard names across CSET

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]

[daflack]

Looks good to me, and the test makes sense. It might be worth getting @jfrost-mo to have a quick look at it from a more detailed technical perspective. Also needs rebasing to be up-to-date with main.

[jfrost-mo]

Looking like a good change. My main comment is to better handle the case where the STASH code isn't in the STASH_TO_LFRIC dictionary.

Once you've addressed the comments I'll re-review.

[ukmo-huw-lewis]

Agree with James' further technical suggestions, and have committed those to branch. Have successfully rerun tests.
Return to @daflack for review check/sign-off prior to merging.

[daflack]

Looking good. Just one minor comment, and there appears to be one test failing.

[daflack]

It just needs one more test to make sure the exception is raised when no stash is present works then it will be good to go.

[ukmo-huw-lewis]

New test added, and checked working as intended. Ready for review

[daflack]

Looks good and makes sense to me. @jfrost-mo do you want one final check before approval?

[jfrost-mo]

Looking good. I've commented with a couple minor documentation tweak, but happy for you to merge when done.