### Description

There is currently no way to pass an `init_command` connection argument for a mysql connection when using either the `mysqlclient` or `mysql-connector-python` libraries with the MySql provider's `MySqlHook`.

Documentation for connection arguments for `mysqlclient` library, listing `init_command`:
https://mysqlclient.readthedocs.io/user_guide.html?highlight=init_command#functions-and-attributes

Documentation for connection arguments for `mysql-connector-python` library, listing `init_command`:
https://dev.mysql.com/doc/connector-python/en/connector-python-connectargs.html

There can be many uses for `init_command`, but also what comes to mind is why do we explicitly provide support to certain connection arguments and not others?

### Use case/motivation

For my own use right now I am currently am subclassing the hook and then altering the connection arguments to pass in `init_command` to set the `time_zone` session variable to UTC at connection time, like so:

```python
conn_config['init_command'] = r"""SET time_zone = '+00:00';"""
```

Note: This is just an example, there can be many other uses for `init_command` besides the example above. Also, I am aware there is a `time_zone` argument for connections via the `mysql-connector-python` library, however that argument is not supported by connections made with `mysqlclient` library. Both libraries do support the `init_command` argument.

### Related issues

_No response_

### Are you willing to submit a PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

dejson_ssl = conn.extra_dejson["ssl"]
            if isinstance(dejson_ssl, str):
                dejson_ssl = json.loads(dejson_ssl)
            conn_config["ssl"] = dejson_ssl
        if conn.extra_dejson.get("ssl_mode", False):
            conn_config["ssl_mode"] = conn.extra_dejson["ssl_mode"]
        if conn.extra_dejson.get("unix_socket"):
            conn_config["unix_socket"] = conn.extra_dejson["unix_socket"]
        if self.local_infile:
            conn_config["local_infile"] = 1
        return conn_config
    def _get_conn_config_mysql_connector_python(self, conn: Connection) -> dict:
        conn_config = {
            "user": conn.login,
            "password": conn.password or "",
            "host": conn.host or "localhost",
            "database": self.schema or conn.schema or "",
            "port": int(conn.port) if conn.port else 3306,
        }
        if self.local_infile:
            conn_config["allow_local_infile"] = True
        
        for key, value in conn.extra_dejson.items():
            if key.startswith("ssl_"):
                conn_config[key] = value
        return conn_config
    def get_conn(self) -> MySQLConnectionTypes: