qproperty_p.h: fix -Wshadow in notify()

Clang warning:
.../qproperty_p.h:666:58: warning: declaration shadows a local variable [-Wshadow]
  666 |                             if (QPropertyObserverPointer observer = d.firstObserver())
      |                                                          ^
.../qproperty_p.h:660:46: note: previous declaration is here
  660 |                 if (QPropertyObserverPointer observer = d.firstObserver()) {
      |

Fix by abbreviating the variable name in if statement.

Pick-to: 6.8
Change-Id: I7905de08f15124466f8aa587691b2880c889199f
Reviewed-by: Ulf Hermann <[email protected]>

src/corelib/kernel/qproperty_p.h

@@ -663,8 +663,8 @@ class QObjectCompatProperty : public QPropertyData<T>
                         if (bd->notifyObserver_helper(this, storage, observer, bindingObservers)
                                 == QtPrivate::QPropertyBindingData::Evaluated) {
                             // evaluateBindings() can trash the observers. We need to re-fetch here.
-                            if (QPropertyObserverPointer observer = d.firstObserver())
-                                observer.notify(this);
+                            if (QPropertyObserverPointer obs = d.firstObserver())
+                                obs.notify(this);
                             for (auto&& bindingPtr: bindingObservers) {
                                 auto *binding = static_cast<QPropertyBindingPrivate *>(bindingPtr.get());
                                 binding->notifyNonRecursive();