[9.x] fix mySQL enum support for db:show command

[lupinitylabs]

The Issue

Currently, the new db:show console command throws a Doctrine\DBAL\Exception if any table in the application uses ENUM columns on a MySQL database:

The Fix

The Doctrine Project addresses the issue with MySQL ENUMs in their documentation and as a global workaround suggests mapping the type to VARCHARs to mitigate the issue.

This PR registers such a type mapping dynamically within the command for all MySQL platforms.

Further unsupported types

The same problem exists for POINT types, but I first wanted to see if there is an intent to address these issues. If the fix is appreciated, I'm happy to add one for POINTs too.

[lupinitylabs]

I noticed a pull request has been opened to address this in the meantime, I am closing this for now in favor of #43635.