(chore): disallow AnnData(...) with non-csr{r,c} matrices/arrays

[ilan-gold]

• Towards (chore): clean up use of spmatrix and sparray #1649, removing the ability to instantiate the class externally is a great start (thanks to @flying-sheep for the reminder: Replace spmatrix with _CSMatrix as appropriate scanpy#3431 (comment))
• Tests added
• Release note added (or unnecessary)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.64%. Comparing base (9120c4d) to head (4da83bf).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1829      +/-   ##
==========================================
- Coverage   86.06%   83.64%   -2.43%     
==========================================
  Files          40       40              
  Lines        6267     6268       +1     
==========================================
- Hits         5394     5243     -151     
- Misses        873     1025     +152     

Files with missing lines	Coverage Δ
src/anndata/_core/storage.py	100.00% <100.00%> (ø)

... and 8 files with indirect coverage changes

[flying-sheep]

You think we should support bsr_array?

[ilan-gold]

I think it could be worth opening an issue but we should probably fully close the linked issue first and then proceed with adding more.

[ilan-gold]

I'd rather make things strict first and then relax rather than going from the current ambiguous state to ambiguous + another format.