Fix broken 2D space view heuristics in Python Notebooks

[Wumpf]

What

• Fixes Spatial heuristics are broken when when run inside a notebook #5654

could in theory affect also non-notebooks, but practically in only manifested there.
Fixes a few typos I encountered on the way and added a new pixi command for building the rerun webviewer wasm.

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using newly built examples: app.rerun.io
  • Using examples from latest main build: app.rerun.io
  • Using full set of examples from nightly build: app.rerun.io
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!

• PR Build Summary
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[github-actions]

Size changes

Name	main	5674/merge	Change
rrt-star.rrd	8.16 MiB	6.73 MiB	-17.52%