Move AA_QtQuickUseDefaultSizePolicy out of Tech Preview

Pick-to: 6.8
Change-Id: Ibdd23455c266af6748aca9de859ea21caac50634
Reviewed-by: Santhosh Kumar <santhosh.kumar.selvaraj@qt.io>

src/corelib/global/qnamespace.h

@@ -423,7 +423,7 @@ namespace Qt {
     enum ApplicationAttribute
     {
         // AA_ImmediateWidgetCreation = 0,
-        AA_QtQuickUseDefaultSizePolicy = 1 QT_TECH_PREVIEW_API,
+        AA_QtQuickUseDefaultSizePolicy = 1,
         AA_DontShowIconsInMenus = 2,
         AA_NativeWindows = 3,
         AA_DontCreateNativeWidgetSiblings = 4,

src/corelib/global/qnamespace.qdoc

@@ -93,9 +93,6 @@
            with the layout can be overridden by explicitly setting
            \l{Layout::fillWidth}{Layout.fillWidth} or
            \l{Layout::fillHeight}{Layout.fillHeight}.
-           \b Note: This API is considered tech preview and may change or be removed in future
-           versions of Qt.
-
 
     \value AA_DontShowIconsInMenus Actions with the Icon property won't be
            shown in any menus unless specifically set by the