modals: move HyprFocusGrab out of common Modal

quickshell/Modals/PolkitAuthModal.qml

@@ -1,4 +1,6 @@
 import QtQuick
+import Quickshell
+import Quickshell.Hyprland
 import qs.Common
 import qs.Modals.Common
 import qs.Services
@@ -9,6 +11,11 @@ DankModal {
 
     layerNamespace: "dms:polkit"
 
+    HyprlandFocusGrab {
+        windows: [root]
+        active: CompositorService.isHyprland && root.shouldHaveFocus
+    }
+
     property string passwordInput: ""
     property var currentFlow: PolkitService.agent?.flow
     property bool isLoading: false