Nonsensical OUString null check

...ever since at least d32b3a714f "#i106421#: move
svx/source/cui to cui".  (That happened to redundantly check for non-empty url,
too; maybe in the distant past GetScriptURL returned a pointer.)

Change-Id: I6139db1d4b1fdcf5325895569de293dd89e36d9f

cui/source/customize/selector.cxx

@@ -993,7 +993,7 @@ void
 SvxScriptSelectorDialog::UpdateUI()
 {
     OUString url = GetScriptURL();
-    if ( url != nullptr && !url.isEmpty() )
+    if ( !url.isEmpty() )
     {
         OUString sMessage =
             m_pCommands->GetHelpText(m_pCommands->FirstSelected());