feat!: support exponential brightness curve

I don't need most of the fluff for handling other types of displays, and getting rid of it lets me do something a lot nicer: add an exponential-gamma brightness display.

modules/osd/Wrapper.qml

@@ -8,7 +8,6 @@ Item {
     id: root
 
     required property var uiState
-    required property ShellScreen screen
 
     visible: width > 0
     implicitWidth: 0
@@ -61,6 +60,5 @@ Item {
         id: content
 
         uiState: root.uiState
-        monitor: Brightness.getMonitorForScreen(root.screen)
     }
 }