* contracts-bedrock: delete more dead code

Removes legacy getters that read hh deploy artifacts from disk.
These are no longer used since the hh deploy artifacts no longer
exist. It is expected that for doing deployments, either the address
is populated into the `Artifacts` contract at runtime or the contract
addresses are populated via `CONTRACT_ADDRESSES_PATH` env var which
points to a JSON file in the superchain-registry repo.

* lint: fix