MySql connector integration tests should be independent from each other

io.debezium.connector.mysql.MySqlConnectorIT::shouldValidateAcceptableConfiguration makes some assumptions and asserts around tables created by the io.debezium.connector.mysql.MetadataIT::shouldLoadMetadataViaJdbc test case.

Each connector integration test should not depend and assert on anything else other than what the Docker image(s) inserts as startup-data and what the test case itself does.