Cannot create colobar for contour/ missing plots entry in contour

[ArneSpang]

• are you running newest version (version from docs) ? - yes
• can you reproduce the bug with a fresh environment ? (]activate --temp; add Makie) - yes
• What platform + GPU are you on? - Ubuntu 22.04 + NVIDIA RTX A4000

I was trying to put a contour plot over a heatmap (of a different dataset) and have two colorbars. But I cannot create one for the contour plot. After asking about this (https://discourse.julialang.org/t/multiple-colobars/116970/6), @lazarusA noticed that the plots entry is not present in the contour object. MWE and error message below:

using CairoMakie
x   = y = 1:0.2:20
f1(x,y) =    (x + 2y^2) * abs(sin(y) + cos(x))
z1  = [f1(x,y) for x in x, y in y]
fig = Figure(resolution=(350,300), fontsize = 14)
ax1 = Axis(fig, aspect = 1, xlabel = "x", ylabel = "y")
p1  = contour!(ax1, x, y, z1, colormap=:roma)
cb1 = Colorbar(fig, p1, width = 10, height = Relative(0.8), ticklabelsize = 10, tickalign = 1)

ERROR: Multiple colormaps found for plot MakieCore.Text{Tuple{Vector{Point{2, Float32}}}}, please specify which one to use manually. Please overload `Makie.extract_colormap(::MakieCore.Text{Tuple{Vector{Point{2, Float32}}}})` to allow for the automatical creation of a Colorbar.

[jkrumbiegel]

The plots entry is there (it's just not an attribute and might be hidden from the tab-completion). The issue is that contour is a composite plot of a lines plus a text plot, and the automatic colormap detection which we added at some point does not pick up the info we want because both lines and text in principle have color information. Although I was also not able to quickly fix it by adding a Contour specific method to extract_colormap which just called that on the lines component, that returned nothing instead of the expected info. Maybe there's something unusual in the structure.