LineElement in legend does not respect colormap attribute

[asinghvi17]

Plotting a LineElement of a line with a colormap does not show a variably coloured line. Explicitly providing color colormap to the line element results in the line being colored in the viridis colormap, irrespective of the colormap provided.

I will hopefully be able to push a quick PR fixing this tonight, but keeping this up here in case some issue arises.

[jkrumbiegel]

It wasn't assumed that a line would be colormapped in a legend, that's why it doesn't have that attribute.

[laikq]

This is relevant for me, since I want to refer to colors used in the plot from the legend. This also affects legends generated using axislegend and the label keyword:

x = 1:10
f, ax, _ = lines(x, x.^2; color=1, colormap=:tab10, colorrange=(1,10), label="test")
axislegend(ax)
f

Throws "Cannot determine a colorrange automatically for single number color value. Pass an explicit colorrange", on CairoMakie v0.10.10 and Julia 1.9.3.