Fixed MyPy errors introduced by new mysql-connector-python

[potiuk]

The new (8.0.32) mysql-connector-python introduces more typing and failed our MySQL provider mypy tests (because we are handling also other mysql clients)

Adding some excludes and handling None better for description solves the problem

---

^ Add meaningful description above

Read the Pull Request Guidelines for more information.
In case of fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in a newsfragment file, named {pr_number}.significant.rst or {issue_number}.significant.rst, in newsfragments.

[uranusjr]

What error does this ignore? (Also other ignores below.)

[potiuk]

See https://github.com/apache/airflow/actions/runs/3943690729/jobs/6749107020 for example:

airflow/providers/mysql/hooks/mysql.py:81: error: "bool" not callable 
[operator]
                conn.autocommit(autocommit)
                ^
airflow/providers/mysql/hooks/mysql.py:96: error: Item
"MySQLConnectionAbstract" of "Union[Any, MySQLConnectionAbstract]" has no
attribute "get_autocommit"  [union-attr]
                return conn.get_autocommit()
                       ^
airflow/providers/mysql/hooks/mysql.py:202: error: Attribute function "close"
with type "Callable[[], Any]" does not accept self argument  [misc]
            conn.close()
            ^
airflow/providers/mysql/hooks/mysql.py:215: error: Attribute function "close"
with type "Callable[[], Any]" does not accept self argument  [misc]
            conn.close()
            ^
airflow/providers/mysql/hooks/mysql.py:286: error: Attribute function "close"
with type "Callable[[], Any]" does not accept self argument  [misc]
            conn.close()
            ^
airflow/providers/apache/hive/transfers/mysql_to_hive.py:[146](https://github.com/apache/airflow/actions/runs/3943690729/jobs/6749107020#step:6:147): error: Item
"None" of
"Union[Any, List[Tuple[str, int, None, None, None, None, Union[bool, int], int, int]], None]"
has no attribute "__iter__" (not iterable)  [union-attr]
                for field in cursor.description:
                             ^
airflow/providers/apache/hive/transfers/mysql_to_hive.py:151: error: Attribute
function "close" with type "Callable[[], Any]" does not accept self argument 
[misc]
                conn.close()
                ^
Found 7 errors in 2 files (checked 930 source files)

I thiink it is a wrong typing coming from bad interpretation of our MySQL union typing. I have not figured out how to do it "properly" - but if you have an idea how to fix it better - I am all ears.

[uranusjr]

I’ll look into it later, merging this first wouldn’t break anything.

[potiuk]

:D I thought you will be ok with it :)