Add blueprint to Objectron example

[abey79]

What

Add blueprint to Objectron example. I've removed all frame-based stuff in favour of reprojecting world stuff into the 2D space view ✨

• Fixes Examples should not manually reproject things across 3D<>2D views #3412

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  • 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
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[Wumpf]

yay!
as per slack discussion we're aware that this removes some media pipe 2D stuff, but it's almost the same as the projection anyways and it's more important to demonstrate what rerun can do