fix two damage artifact causes

1. when adding a full damange, that must not replace existing (larger) repaints
2. emit geometryChanged before invoking and to update shadowGeometry through addRepaintFull

BUG: 324560
FIXED-IN: 4.11.2

composite.cpp

@@ -989,7 +989,7 @@ void Toplevel::addDamageFull()
         return;
 
     damage_region = rect();
-    repaints_region = rect();
+    repaints_region |= rect();
 
     emit damaged(this, rect());
 }

events.cpp

@@ -1521,6 +1521,7 @@ void Unmanaged::configureNotifyEvent(XConfigureEvent* e)
         addWorkspaceRepaint(visibleRect());  // damage old area
         QRect old = geom;
         geom = newgeom;
+        emit geometryChanged(); // update shadow region
         addRepaintFull();
         if (old.size() != geom.size())
             discardWindowPixmap();