This fixes the issue that on LidOpen-resume the brightness might get restoredtwo times. Once to the correct vallue and once incorrectly to 0.
To archive this it uses the same simple "don't restore to 0"-policy as is usedin dimdisplay.cpp, dpms.cpp, and handlebuttonevent.cpp.
I actually only tested this patch on 5.27.8, but considering the simplicity of the patch I hope this is fine.