QAccessible test: skip focusChild on wayland

The test implicitly relies on window activation as QWidget only emits
accessibility events for focus changes in the active window. So skip it
on platforms that don't support WindowActivation and remove it from
the blacklist.

Fixes: QTBUG-109763
Pick-to: 6.5
Change-Id: I67d9a95f4f36b5271fe53ae90140a28770566c83
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

tests/auto/other/qaccessibility/BLACKLIST

@@ -1,3 +0,0 @@
-[focusChild]
-# QTBUG-109763
-wayland

tests/auto/other/qaccessibility/tst_qaccessibility.cpp

@@ -4156,6 +4156,9 @@ private:
 
 void tst_QAccessibility::focusChild()
 {
+    if (!QGuiApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::WindowActivation))
+        QSKIP("Platform does not support window activation");
+
     {
         QMainWindow mainWindow;
         QtTestAccessibleWidget *widget1 = new QtTestAccessibleWidget(0, "Widget1");