[hotfix][table] Use two spaces for MODIFY DEFINITION QUERY

Author: snuyanzin

flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/operations/materializedtable/AlterMaterializedTableChangeOperation.java

@@ -119,7 +119,7 @@ private static String toString(TableChange tableChange) {
         } else if (tableChange instanceof ModifyDefinitionQuery) {
             ModifyDefinitionQuery definitionQuery = (ModifyDefinitionQuery) tableChange;
             return String.format(
-                    " MODIFY DEFINITION QUERY TO '%s'", definitionQuery.getDefinitionQuery());
+                    "  MODIFY DEFINITION QUERY TO '%s'", definitionQuery.getDefinitionQuery());
         } else {
             return AlterTableChangeOperation.toString(tableChange);
         }

flink-table/flink-table-planner/src/test/java/org/apache/flink/table/planner/operations/SqlNodeToOperationSqlCreateOrAlterMaterializedTableConverterTest.java

@@ -208,7 +208,7 @@ void testCreateOrAlterMaterializedTableForExistingTable() throws TableNotExistEx
                         "CREATE OR ALTER MATERIALIZED TABLE builtin.default.mt\n"
                                 + "  ADD `e` STRING ,\n"
                                 + "  ADD `f` STRING ,\n"
-                                + " MODIFY DEFINITION QUERY TO 'SELECT `t1`.`a`, `t1`.`b`, `t1`.`c`, `t1`.`d`, `t1`.`d` AS `e`, CAST('123' AS STRING) AS `f`\n"
+                                + "  MODIFY DEFINITION QUERY TO 'SELECT `t1`.`a`, `t1`.`b`, `t1`.`c`, `t1`.`d`, `t1`.`d` AS `e`, CAST('123' AS STRING) AS `f`\n"
                                 + "FROM `builtin`.`default`.`t1` AS `t1`',\n"
                                 + "  SET 'format' = 'json2',\n"
                                 + "  RESET 'connector',\n"