client: Destroy window manager integration before display

Like the globals window manager integration needs the display to be
alive.

Fixes: QTBUG-121364
Change-Id: I3bf10737f9c1aa6d0b3c34d2268532ea6fc4e957
Reviewed-by: David Edmundson <davidedmundson@kde.org>

src/plugins/platforms/wayland/qwaylanddisplay.cpp

@@ -373,6 +373,7 @@ QWaylandDisplay::~QWaylandDisplay(void)
 
     // Reset the globals manually since they need to be destroyed before the wl_display
     mGlobals = {};
+    mWindowManagerIntegration.reset();
 
     if (object())
         wl_registry_destroy(object());