set dialog background for settings in dark theme (fix #11096)
set dialog background for settings in dark theme (fix #11096)

cgeo/cgeo,cgeo/cgeo,tobiasge/cgeo,rsudev/c-geo-opensource,rsudev/c-geo-opensource,tobiasge/cgeo,cgeo/cgeo,tobiasge/cgeo,rsudev/c-geo-opensource,cgeo/cgeo