feat: Allow using accessors in sc.get.aggregate

[flying-sheep]

• Closes #
• Tests included or not required because:

• Release notes not necessary because:

[codecov]

Codecov Report

❌ Patch coverage is 95.55556% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.03%. Comparing base (dde009a) to head (82bb6ad).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/scanpy/get/get.py	91.66%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4199      +/-   ##
==========================================
+ Coverage   79.91%   80.03%   +0.12%     
==========================================
  Files         121      121              
  Lines       12949    13030      +81     
==========================================
+ Hits        10348    10429      +81     
  Misses       2601     2601              

Flag	Coverage Δ
hatch-test.low-vers	78.98% <82.22%> (-0.06%)	⬇️
hatch-test.pre	79.94% <91.66%> (+0.07%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/scanpy/_settings/presets.py	90.97% <100.00%> (+0.12%)	⬆️
...c/scanpy/experimental/pp/_highly_variable_genes.py	94.23% <100.00%> (ø)
src/scanpy/experimental/pp/_normalization.py	94.56% <100.00%> (ø)
src/scanpy/get/__init__.py	100.00% <ø> (ø)
src/scanpy/get/_aggregated.py	96.60% <100.00%> (+2.68%)	⬆️
src/scanpy/metrics/_gearys_c.py	100.00% <100.00%> (ø)
src/scanpy/metrics/_morans_i.py	100.00% <100.00%> (ø)
src/scanpy/preprocessing/_highly_variable_genes.py	94.63% <100.00%> (ø)
src/scanpy/preprocessing/_normalization.py	94.66% <100.00%> (ø)
src/scanpy/preprocessing/_pca/__init__.py	91.92% <100.00%> (ø)
... and 7 more

[ilan-gold]

I don't see any tests for the added behavior i.e., around by=A.obsm["foo"][:, 1]