(fix): python debugger dask h5 meta array

[ilan-gold]

Noticed while using the python debugger - dask sets block_info to None when run this way, which causes the function to error but setting meta (probably a good idea anyway) prevents this.

This also drive-by fixes an "internal" bug which did not have an effect downstream, but still noticed. And I added a test (which passes anyway without this change, but still a sensible test).

• Closes #
• Tests added
• Release note added (or unnecessary): does not change runtime behavior

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.48%. Comparing base (d61e09c) to head (545393a).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1774      +/-   ##
==========================================
- Coverage   87.01%   84.48%   -2.53%     
==========================================
  Files          40       40              
  Lines        6059     6059              
==========================================
- Hits         5272     5119     -153     
- Misses        787      940     +153     

Files with missing lines	Coverage Δ
src/anndata/_io/specs/lazy_methods.py	97.50% <100.00%> (-2.50%)	⬇️

... and 8 files with indirect coverage changes

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