Show _some_ data automatically in 3D panel

[jtbandes]

When using a new, blank 3D panel and connecting to any data source, the panel doesn't display anything until the user configures it in settings. This causes user confusion (e.g. foxglove/ws-protocol#278 (comment)). We should at least display some topics by default.

Originally, the default behavior of the new 3d panel was to subscribe to all available topics, but that was deemed too chaotic and data-intensive. Hiding only camera images was proposed, but we settled on hiding everything by default:

• https://github.com/foxglove/studio/issues/3643
• https://github.com/foxglove/studio/issues/3692

We've discussed displaying a grid by default (and some technical limitations that make this harder than it sounds):

• Add a default grid to the 3d panel #373
• New3D panel doesn't show grid until data is available (frame error) #499

Separately from the grid, though, it would still be better to show some actual user data without requiring the user to discover and understand panel settings.

Of course, if we choose to show some but not all user data by default, it might cause confusion when users don't understand some data is automatically hidden, and just assume that some of their data doesn't work. So we may need to improve settings discoverability as well. (cc @2metres @ocin-rye @esthersweon)

Copying my ideas from https://github.com/foxglove/studio/issues/3643#issuecomment-1164941057:

Here are some ideas for heuristics if we decide that showing all topics is too much.

• Prioritize topics by data size, if we know the size, otherwise sort by schema in order to estimate how expensive it is to show topics.
  • e.g. if we have to choose between a Pose or a Marker and an Image message, we should drop the Image first since it's likely to be much more expensive to visualize.
  • Then show at most 20 topics by default in this priority order.
• If we didn't turn on all topics by default, show the user a message/popup saying something to the effect of "some topics are hidden, open settings sidebar to customize".
• Keep in mind that the same layout may be used with different data sources over time, or a single live data source that gains more topics. So we have to respond dynamically to new topics coming online. This might be tricky since we don't want to store the list of "seen topics" in the layout. We might need to keep careful track of which topics the user has manually toggled on/off, and only dynamically decide what to do for topics that have never been manually toggled. [related: Setting to Automatically Subscribe to Visualization Topics in 3D Tab #343]
• Or just don't do any of this, because it sounds complicated and fragile

And some more ideas:

• Show all topics of certain types by default (markers, poses, grids, etc.) but not cameras, unless there are only cameras available