This patch implements the list panel system D7490 for grease pencil shader effects. It also moves their drawing to a callback in ShaderFxTypeInfo in line with the extensible architecture refactoring goal T75724.
The implementation is exactly the same as for the modifier patch.
@Matias Mendiola (mendio) and I worked out the layout updates together.
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This patch is a diff from D7978, which is a diff from D7499, so it might not be the easiest patch to apply. Aside from the layouts, everything is the same changes as the other patches though.

















