Touch event dispatching: change qCWarning to qCDebug if no target window

Warning messages are by default emitted for qt.* logging categories. But
neither the end user nor the application developer can do anything about
this particular warning (which gets emitted on macOS when using the
touch pad) - it's only useful for Qt developers.

So change the logging level to debug.

Pick-to: 6.8 6.7 6.5
Fixes: QTBUG-125589
Change-Id: I36e6e553494054488209139e3238b7bd11bd170a
Reviewed-by: Shawn Rutledge <[email protected]>

src/gui/kernel/qguiapplication.cpp

@@ -3102,7 +3102,7 @@ void QGuiApplicationPrivate::processTouchEvent(QWindowSystemInterfacePrivate::To
         }
         // If we somehow still don't have a window, we can't deliver this touchpoint.  (should never happen)
         if (Q_UNLIKELY(!window)) {
-            qCWarning(lcPtrDispatch) << "skipping" << &tempPt << ": no target window";
+            qCDebug(lcPtrDispatch) << "skipping" << &tempPt << ": no target window";
             continue;
         }
         QMutableEventPoint::update(tempPt, ep);