Xarray datatree support

[melonora]

This PR adds utility functions to support the transition to xarray version that includes direct support for DataTree with the datatree library being archived. Quite some methods are not available at the DataTree level anymore, some of which were being used in napari-spatialdata.

The decorator from scverse/spatialdata#752 is being used here to apply transpose and reindexing on the DataTree structure that we support. Tests pass locally.

[codecov]

Codecov Report

Attention: Patch coverage is 81.25000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 66.49%. Comparing base (69105e0) to head (36633ba).
Report is 18 commits behind head on main.

Files with missing lines	Patch %	Lines
src/napari_spatialdata/_widgets.py	40.00%	3 Missing ⚠️
src/napari_spatialdata/_scatterwidgets.py	0.00%	1 Missing ⚠️
src/napari_spatialdata/_viewer.py	66.66%	1 Missing ⚠️
src/napari_spatialdata/utils/_utils.py	91.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #329      +/-   ##
==========================================
+ Coverage   63.08%   66.49%   +3.40%     
==========================================
  Files          19       19              
  Lines        2636     2701      +65     
==========================================
+ Hits         1663     1796     +133     
+ Misses        973      905      -68     

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