[9.x] Remove index name when adding primary key on MySQL

[hafezdivandari]

It is kind of a bug fix, MySQL doesn't have index name for primary key, check the syntax on 5.7 and 8.0

ALTER TABLE tbl_name
    [alter_option [, alter_option] ...]
    [partition_options]

alter_option: {
    table_options
  | ADD [CONSTRAINT [symbol]] PRIMARY KEY
        [index_type] (key_part,...)
        [index_option] ...
  | DROP PRIMARY KEY
}

key_part: {col_name [(length)] | (expr)} [ASC | DESC]

index_type:
    USING {BTREE | HASH}

index_option: {
    KEY_BLOCK_SIZE [=] value
  | index_type
  | WITH PARSER parser_name
  | COMMENT 'string'
  | {VISIBLE | INVISIBLE}
}