Automated graph checks

[teh-cmc]

Most of it was already automated, just added the missing multi-graphs test so we can finally get rid of the manual check.

[github-actions]

Web viewer built successfully. If applicable, you should also test it:

• I have tested the web viewer

Result	Commit	Link	Manifest
✅	ba725f1	https://rerun.io/viewer/pr/8982	+nightly +main

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