Fix ouroborus-consensus serialization roundtrip test

[aniketd]

Description

This change has been tested locally against ouroboros-consensus master a6e6707974d12fecd40650e6fb995d2058772d37 by pointing cabal to a local checkout of cardano-ledger at the tag cardano-ledger-shelley-1.9.0.0 with the same change.

Resolves #3740

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• When applicable, versions are updated in .cabal and CHANGELOG.md files according to the
  versioning process.
• The version bounds in .cabal files for all affected packages are updated. If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• All visible changes are prepended to the latest section of a CHANGELOG.md for the affected packages. New section is never added with the code changes. (See RELEASING.md)
• Code is formatted with fourmolu (use scripts/fourmolize.sh)
• Cabal files are formatted (use scripts/cabal-format.sh)
• hie.yaml has been updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[lehins]

Very nice find.

Could you also open a ticket on the consensus repo, that will track re-enabling those roundtrip tests whenever they will be integrating new ledger

[lehins]

Also looks like our golden tests need fixing, which is expected
(note on the consensus ticket that they'll have to do the same)