### 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)

DEFAULT_AUTOCOMMIT = "default"
    def __init__(self):
        self._autocommit = self.DEFAULT_AUTOCOMMIT
    @property
    def autocommit(self):
        return self._autocommit
    @autocommit.setter
    def autocommit(self, autocommit):
        self._autocommit = autocommit
class TestMySqlHook:
    def setup_method(self):
        self.cur = mock.MagicMock(rowcount=0)
        self.conn = mock.MagicMock()
        self.conn.cursor.return_value = self.cur
        conn = self.conn
        class SubMySqlHook(MySqlHook):
            conn_name_attr = "test_conn_id"
            def get_conn(self):
                return conn
        self.db_hook = SubMySqlHook()
    @pytest.mark.parametrize("autocommit", [True, False])
    def test_set_autocommit_mysql_connector(self, autocommit):
        conn = MockMySQLConnectorConnection()
        self.db_hook.set_autocommit(conn, autocommit)
        assert conn.autocommit is autocommit
    def test_get_autocommit_mysql_connector(self):
        conn = MockMySQLConnectorConnection()
        assert self.db_hook.get_autocommit(conn) == MockMySQLConnectorConnection.DEFAULT_AUTOCOMMIT
    def test_set_autocommit_mysqldb(self):