fix(nargo): restore nargo codegen-verifier functionality

[TomAFrench]

Related issue(s)

Resolves #

Description

Summary of changes

Looks like we got a bit ahead of ourselves and started using eth_contract_from_vk against a commit of aztec_backend where that isn't implemented yet. If you run nargo codegen-verifier on v0.4.0 you get

$ nargo codegen-verifier
The application panicked (crashed).
Message:  not yet implemented: use `eth_contract_from_cs` for now
Location: /home/tom/.cargo/git/checkouts/aztec_backend-a697fb631cbad807/2617835/barretenberg_static_lib/src/acvm_interop/smart_contract.rs:10

This is a bug. Consider opening an issue at https://github.com/noir-lang/noir/issues/new?labels=bug&template=bug_report.yml

This PR reverts to eth_contract_from_cs and adds an integration test that if you run codegen-verifier the command succeeds and you get some file created.

I haven't made any change to nargo::ops::codegen_verifier as that's backend agnostic and I don't want to make a breaking change to fix this.

Dependency additions / changes

Test additions / changes

Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt with default settings.
• I have linked this PR to the issue(s) that it resolves.
• I have reviewed the changes on GitHub, line by line.
• I have ensured all changes are covered in the description.

Documentation needs

• This PR requires documentation updates when merged.

Additional context