fix: add label to volume where they exist

[xgui3783]

No description provided.

[codecov-commenter]

Codecov Report

Merging #272 (002ee51) into main (5d8f673) will increase coverage by 0.03%.
The diff coverage is 38.96%.

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@@            Coverage Diff             @@
##             main     #272      +/-   ##
==========================================
+ Coverage   35.75%   35.79%   +0.03%     
==========================================
  Files          59       59              
  Lines        4984     5026      +42     
==========================================
+ Hits         1782     1799      +17     
- Misses       3202     3227      +25     

Impacted Files	Coverage Δ
siibra/features/basetypes/volume_of_interest.py	41.93% <0.00%> (-2.19%)	⬇️
siibra/volumes/nifti.py	18.91% <16.66%> (-0.53%)	⬇️
siibra/features/anchor.py	22.68% <21.73%> (-0.07%)	⬇️
siibra/volumes/volume.py	50.65% <33.33%> (-2.78%)	⬇️
siibra/volumes/neuroglancer.py	21.42% <56.25%> (+0.79%)	⬆️
siibra/volumes/gifti.py	35.93% <71.42%> (+4.35%)	⬆️
siibra/__init__.py	66.66% <100.00%> (+1.55%)	⬆️
siibra/commons.py	38.08% <100.00%> (ø)

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