[CP] [to #55710902]Support case when expr in decl default value should not use '()'.

src/pl/parser/pl_parser_mysql_mode.y

@@ -1791,7 +1791,7 @@ sp_data_type:
 
 opt_sp_decl_default:
     /*Empty*/ { $$ = NULL; }
-  | DEFAULT expr
+  | DEFAULT default_expr
     {
       malloc_non_terminal_node($$, parse_ctx->mem_pool_, T_SP_DECL_DEFAULT, 1, $2);
     }