Use `mysql:latest` for mysql CI job and update driver code accordingly (#36025)

* Adjust mysql container env

* Setting the HOST can cause trouble they said

https://hub.docker.com/_/mysql. Let's try it without then.

* Also MYSQL_USER doesn't play well with empty password

* Cast results of temporal extract to decimal

* Update test

* Update test

* Revert casting temporal-extract results to decimals

* Handle mysql YEAR type as a number instead of a date

* Cleanup