Regression: plotting GeometryBasics.MultiPoint no longer works

[asinghvi17]

• what version of Makie are you running? (]st -m Makie) 0.22.0
• can you reproduce the bug with a fresh environment ? (]activate --temp; add Makie) yes
• What platform + GPU are you on? irrelevant

In v0.21, and with GeometryBasics v0.4.x, MultiPoints were subtypes as AbstractVectors of Points, so plot recipes just worked. Now they aren't, so plotting fails.

Should we add recipes for multipoints to Makie? It's a pretty common thing in GIS to want to plot these kinds of things, and the way we implemented plot recipes for Makie means that geometries are converted directly to GeometryBasics geoms.

MWE:

using Makie, GeometryBasics
scatter(GeometryBasics.MultiPoint(rand(Point2f, 10))

(yields conversion error - no recipe defined)