[Non-Touch] Don't add touch-related menu items (#8608)

They were ending up orphaned as "New:" in the top menu first tab.

frontend/ui/elements/page_turns.lua

@@ -139,4 +139,13 @@ if Device:hasKeys() then
     })
 end
 
+if not Device:isTouchDevice() then
+    if Device:hasKeys() then
+        -- We just need the last item added above.
+        PageTurns = PageTurns.sub_item_table[#PageTurns.sub_item_table]
+    else
+        PageTurns = {} -- no menu item
+    end
+end
+
 return PageTurns