Wrong colors in Plasma 6 X11 Panel when using Mesa 24.2.x with llvmpipe

When using the Plasma 6 X11 session with llvmpipe (e.g. in a VM that doesn't provide a proper GPU), the colors in the panel are off - lots of icons turn orange-ish (looks like blue and red are exchanged?).

This is what it looks like with 24.2.x:

This is what it should look like (and what it does look like with a proper GPU or with Mesa 24.1.x llvmpipe):

(Note that you need to fix #11818 (closed) - e.g. by reverting the problematic commit referenced there - to see this; otherwise there will be no GLX context, but the colors will look right).