Visualize images in selection view

[emilk]

Blocked on

• https://github.com/rerun-io/rerun/issues/7051

We currently visualize TensorData in the selection view, but https://github.com/rerun-io/rerun/issues/6844 we plan on splitting these into multiple components, which each on their own is not enough to paint the image.

So how do create a UI for an archetype?

For instance, ImageEncoded is a Blob and a MediaType, and only if we have both can we show it as an image.

Spatial View solution

One solution is to instantiate a miniature SpatialView in the selection panel for compatible archetypes.

This would also allow us to show e.g. an arrow when you select an entity with the Arrow2DIndicator, for instance.

[emilk]

I've added some #[allow(dead_code)] // TODO(#6891) in the code rather than deleting it

[emilk]

We should be able to visualize images again pretty easily by adding a special-case for the component ImageFormat once that lands:

• https://github.com/rerun-io/rerun/issues/7051

It will still be a snow-flake, and a more general solution would be nice

[emilk]

• When selecting the full entity of the image, we should show the image in the UI.
• When selecting the component ImageBuffer, should we show the image in the UI?

For now, it's fine if a selected SegmentationImage is shown in gray-scale, if that makes things easier.