[Bug]: mysql_stmt_execute is not work

### Describe the bug

the ret variable is not initialized, it may be a bug, please check it

https://github.com/oceanbase/obconnector-c/blob/6a6074a2a9dfe21e8f7997d0332a288547294cbc/libmariadb/mariadb_stmt.c#L3693C7-L3693C7

### Environment

linux aarch64

### Fast reproduce steps

NA

### Expected behavior

NA

### Actual behavior

NA

### Additional context

NA…