re-enable code style checks in CI

We've been having build issues recently with the javafmt checks - eg #1400 so they were disabled.
It's worth also seeing if we can enable scalafmt checks.
One thing to be aware of is that we probably need some way to skip test code that is included in our Paradox docs does not have their imports reordered because for the docs, the existing order is deliberate.

Start by locating the CI configuration where javafmt checks were disabled and review how Scala formatting is configured. Check the Paradox documentation examples whose imports must remain in deliberate order; done means the Java formatting checks are re-enabled, Scala formatting is assessed or enabled, and those examples are safely excluded where needed.

Written by the indexing model from the issue text.