Fix site picks: missing from globals

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Change-Id: If0301026e62e7d2b7249af68e336de4ff2ce3f54

UniversalLanguageSelector.hooks.php

@@ -304,7 +304,8 @@ class UniversalLanguageSelectorHooks {
 			$wgULSImeSelectors, $wgULSNoImeSelectors,
 			$wgULSFontRepositoryBasePath,
 			$wgExtensionAssetsPath,
-			$wgWBClientSettings;
+			$wgWBClientSettings,
+			$wgInterwikiSortingSortPrepend;
 
 		// Place constant stuff here (not depending on request context)