Removed unused setup() method in zh driver

[GabrielePalazzo]

Checklist:

• [ ] Reviewers confirm new code works as expected.
• [ ] Tests are passing.
• [ ] Coverage does not decrease.
• [ ] Documentation is updated.

[GabrielePalazzo]

I don't think this will work because setup is still an @abstractmethod of the abstract Instrument.

Yes, I just realized it (and that's why tests are failing). I'll just close it.