wallpapers/color: Add back "ServiceTypes" property in metadata.json
In containmentconfigview.cpp, "Plasma/Wallpaper" is checked if a plugin is of ServiceType Plasma/Wallpaper. BUG: 448625 FIXED-IN: 5.24
In containmentconfigview.cpp, "Plasma/Wallpaper" is checked if a plugin is of ServiceType Plasma/Wallpaper. BUG: 448625 FIXED-IN: 5.24