Handle IF images for Visium HD

[quentinblampey]

Closes #258 with the simple fix we discussed @LucaMarconato!

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.

Project coverage is 50.35%. Comparing base (c4f6cf7) to head (bc5352d).
Report is 90 commits behind head on main.

Files with missing lines	Patch %	Lines
src/spatialdata_io/readers/visium_hd.py	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #261      +/-   ##
==========================================
+ Coverage   43.68%   50.35%   +6.66%     
==========================================
  Files          23       26       +3     
  Lines        2353     2647     +294     
==========================================
+ Hits         1028     1333     +305     
+ Misses       1325     1314      -11     

Files with missing lines	Coverage Δ
src/spatialdata_io/readers/visium_hd.py	17.97% <0.00%> (-0.32%)	⬇️

... and 2 files with indirect coverage changes

[LucaMarconato]

LGTM thanks!