RenderEngineVtk fails to parse this mtl file?

[RussTedrake]

The attached urdf/obj/mtl trio renders differently in our different renderers:

• Meshcat c++, DrakeVisualizer, and MeshLab all (correctly) show the table in grey because it has a grey material specified.
• RenderEngineVtk renders it in red. Note that the urdf does specify a red material for the visual geometry. My unverified assumption is that the RenderEngineVtk is silently failing to parse the mtl file.
• Unfortunately, meshcat-visualizer in python also renders it in red, but I'm not planning to fix that one.

To reproduce, it is enough to add the urdf into the rendering_multibody_plant tutorial with:

table = parser.AddModelFromFile("AirHockeyTable.urdf")
plant.WeldFrames(plant.world_frame(), plant.GetFrameByName("table"))

Expected: The table should be grey in the matplotlib rendered color image produced by ax[0].imshow(color). Actual: The table appears red.

AirHockeyTable.zip

[RussTedrake]

@rpoyner-tri is right, this is a duplicate of #11949