(fix): move zarr import inside try-catch in test helpers

[ilan-gold]

Is there some sort of way to test this? Open to suggestions. ruff does not support custom rules, I think?

• Towards We broke scanpy’s tests #1342
• Tests added
• Release note added (or unnecessary)

[ilan-gold]

Not a huge fan of this, but I think the other option is to create AccessTrackingStore based on some dummy base class, which will error out on construction with a less helpful error. And if we want to raise an error, we're sort of back to this.

[ivirshup]

I think an anndata-mindeps test job would be the way to test this, and then testing all the functionality used by scanpy-mindeps uses under that job. I don't think a static check would be enough here, since a something could always be imported dynamically

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (e07477d) 85.71% compared to head (8f1d056) 83.49%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1343      +/-   ##
==========================================
- Coverage   85.71%   83.49%   -2.23%     
==========================================
  Files          34       34              
  Lines        5455     5460       +5     
==========================================
- Hits         4676     4559     -117     
- Misses        779      901     +122     

Flag	Coverage Δ
gpu-tests	?

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Files	Coverage Δ
anndata/tests/helpers.py	86.99% <80.00%> (-9.20%)	⬇️

... and 6 files with indirect coverage changes