Disable splashScreenModality test: dialog is going under splash screen

That's a bug, but this test causes CI problems until it's fixed.

Task-number: QTBUG-35169
Change-Id: I27b3a61437312d2217743670fa14510d9340d8c1
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Reviewed-by: Simo Fält <simo.falt@digia.com>

tests/auto/other/macgui/tst_macgui.cpp

@@ -142,6 +142,8 @@ void tst_MacGui::splashScreenModality()
     box.setText("accessible?");
     box.show();
 
+    QSKIP("QTBUG-35169");
+
     // Find the "OK" button and schedule a press.
     QAccessibleInterface *interface = wn.find(QAccessible::Name, "OK", &box);
     QVERIFY(interface);