fix(facet): Honor facet size in draw!

[jkrumbiegel]

facet = (; size = FacetSize(...)) worked with draw but errored with draw!:

df = (; x = repeat(1:5, 10), y = rand(50), g = repeat(string.(1:10), inner = 5))
plt = data(df) * mapping(:x, :y, layout = :g) * visual(Lines)

draw!(Figure(), plt; facet = (; size = FacetSize(2.0, (nr, nc) -> 100)))
# MethodError: no method matching clean_facet_attributes(...; size::FacetSize)

_draw! never forwarded facet to compute_axes_grid, so the FacetSize was neither applied to the axis width/height nor used for the wrap layout, and the :size key leaked into clean_facet_attributes. Now plot! forwards facet and _draw! strips :size before facet!, mirroring the non-mutating draw path.

Also bumps the version to v0.12.13.