Fix janky behavior of room drawer swipes

When not modal, dragging the edge of the room drawer to change its width felt very broken.
This seems to be a collision between Qt's dragging logic and our dragging logic,
so we disable theirs if the drawer is not modal

src/qml/RoomDrawer.qml

@@ -19,6 +19,7 @@ Kirigami.OverlayDrawer {
     required property NeoChatConnection connection
 
     width: actualWidth
+    interactive: modal
 
     readonly property int minWidth: Kirigami.Units.gridUnit * 15
     readonly property int maxWidth: Kirigami.Units.gridUnit * 25