Safeguard against invalid user input in render_shapes

[timtreis]

No description provided.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 82.35294% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.36%. Comparing base (17607ba) to head (f08f8f5).

Files with missing lines	Patch %	Lines
src/spatialdata_plot/pl/utils.py	82.35%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #512      +/-   ##
==========================================
- Coverage   84.42%   84.36%   -0.06%     
==========================================
  Files           8        8              
  Lines        2131     2181      +50     
==========================================
+ Hits         1799     1840      +41     
- Misses        332      341       +9     

Files with missing lines	Coverage Δ
src/spatialdata_plot/pl/utils.py	80.26% <82.35%> (+0.06%)	⬆️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[timtreis]

@josenimo could you rerun with this branch? What do you think of the error that is now returned?