Unbreak the ?setlang functionality

This mistake has caused setlang=xx to get stuck and not reload the page.

Bug: T377572
Change-Id: I1dd9aeb1a6c52ade6b60744a8b29cf39f8b85885

resources/js/ext.uls.setlang.js

@@ -68,7 +68,7 @@
 	 */
 	function currentUrlWithoutSetLang() {
 		var url = new URL( location.href );
-		url.searchParams.remove( 'setlang' );
+		url.searchParams.delete( 'setlang' );
 		return url.toString();
 	}