Do not set code when recasting PDOException

[MasterOdin]

Fixes #2098

The PDOException class has the signature int|string $code, which makes it incompatible with most other stdlib exceptions that only allow int $code. While we could probably make a custom exception class or whatever for the recast, I don't think it's worth the hassle, and looking at the DB ecosystem, some amount of it also just drops the code in favor of just using 0 (e.g. cakephp/Database in Database/Driver and have for years that I'm not sure people will really miss it.

The PDOException recast has been happening for the entire existence of this project that I'm somewhat risk adverse to remove the recast.

[MasterOdin]

Having this target 0.next as it is a breaking change assuming there's someone out there relying on what the recast exception code is for doing something.