[FEATURE] Test Set for MySQL Connection

[TheCedarPrince]

Currently, the test set for the MySQL integration via MySQL.jl does not exist yet. We need a test set that covers the following functions within mysql.jl:

• _dbconnect - this function is the core dispatch within DBConnector.jl and is exported for a user

Since MySQL.jl satisfies the DBInterface, creating a test set should be very straightforward. One can create a test that passes a MySQL.Connection object to this dispatch and then makes sure that an error does not occur when returning a DBInterface.connect object.