Handle missing vertexcolor and facecolor in mesh3d

[archmoj]

Fix #4348 & #4349
gl-mesh3d used to stop when encountering a missing vertexcolor or facecolor which is fixed by gl-mesh3d v2.1.2 and v2.1.3 patches.
This PR bumps gl-mesh3d and adds an image test.

@plotly/plotly_js

[alexcjohnson]

rename mising -> missing

missing vertex color reverts to white, but missing face color is omitted. Is that intentional / desirable? Offhand I'd think we'd want the faces to be white as well. Or perhaps a light gray in both cases...

[archmoj]

We could use gray color for both cases which is pretty easy to do.
But I think when encountring missing data we should display the face or vertex as invisible.
In that regard, we could try turning vertices with missing vertexcolor to full transparent.
@alexcjohnson what do you suggest?

[alexcjohnson]

In general I feel like data should not disappear if some secondary characteristic of it (color in this case, but more generally anything beyond its position) is missing or invalid. For example scatter traces with a short marker.color array treat the missing items as black. (that said I see that a short marker.size array yields size=0, this argument would say it should yield the default size)

This is mostly useful for debugging, so you can see what parts you got right and what parts have issues. If your goal is to make a transparent face, you should specify this explicitly rather than relying on an implicit "bad data becomes transparent"

[archmoj]

In general I feel like data should not disappear if some secondary characteristic of it (color in this case, but more generally anything beyond its position) is missing or invalid. For example scatter traces with a short marker.color array treat the missing items as black. (that said I see that a short marker.size array yields size=0, this argument would say it should yield the default size)

This is mostly useful for debugging, so you can see what parts you got right and what parts have issues. If your goal is to make a transparent face, you should specify this explicitly rather than relying on an implicit "bad data becomes transparent"

@alexcjohnson Good call.
Done in 3066f32.

[alexcjohnson]

💃