Make InternalWindowEventFilter::pointerEvent() exclusive

If an internal window doesn't accept the event, we should still stop
traversing the event filter chain because we know that the internal
window is the only receiver of pointer events.

src/input.cpp

@@ -1249,14 +1249,14 @@ public:
             // the handle can be nullptr if the tooltip gets closed while focus updates are blocked
             return false;
         }
-        const bool isAccepted = QWindowSystemInterface::handleMouseEvent(internal,
-                                                                         event->position() - internal->position(),
-                                                                         event->globalPosition(),
-                                                                         event->buttons(),
-                                                                         event->button(),
-                                                                         event->type(),
-                                                                         event->modifiers());
-        return isAccepted;
+        QWindowSystemInterface::handleMouseEvent(internal,
+                                                 event->position() - internal->position(),
+                                                 event->globalPosition(),
+                                                 event->buttons(),
+                                                 event->button(),
+                                                 event->type(),
+                                                 event->modifiers());
+        return true;
     }
     bool wheelEvent(WheelEvent *event) override
     {