(feat): seurat v3 with dask

[ilan-gold]

• Closes Dask support for pp.highly_variable_genes ("seurat_v3" flavor(s)) #2808
• Tests included or not required because:

• Release notes not necessary because:

[codecov]

Codecov Report

Attention: Patch coverage is 96.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 76.62%. Comparing base (d0adc25) to head (f83e3f3).
Report is 24 commits behind head on main.

Files with missing lines	Patch %	Lines
src/scanpy/preprocessing/_highly_variable_genes.py	96.29%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3340      +/-   ##
==========================================
+ Coverage   76.59%   76.62%   +0.02%     
==========================================
  Files         111      111              
  Lines       12827    12880      +53     
==========================================
+ Hits         9825     9869      +44     
- Misses       3002     3011       +9     

Files with missing lines	Coverage Δ
src/scanpy/_utils/__init__.py	76.24% <100.00%> (+0.04%)	⬆️
src/scanpy/preprocessing/_highly_variable_genes.py	95.91% <96.29%> (+0.67%)	⬆️

... and 3 files with indirect coverage changes