make bg image loading async

.config/quickshell/ii/modules/background/Background.qml

@@ -150,6 +150,7 @@ Variants {
             id: wallpaper
             visible: !bgRoot.wallpaperIsVideo
             property real value // 0 to 1, for offset
+            asynchronous: true
             value: {
                 // Range = groups that workspaces span on
                 const chunkSize = Config?.options.bar.workspaces.shown ?? 10;

.config/quickshell/ii/modules/overview/OverviewWindow.qml

@@ -1,7 +1,6 @@
 import qs
 import qs.services
 import qs.modules.common
-import qs.modules.common.widgets
 import qs.modules.common.functions
 import Qt5Compat.GraphicalEffects
 import QtQuick