Remove libs/cardano-ledger-pretty

[TimSheard]

removed libs/cardano-ledger-pretty
Follow on to PR #3973
This library is no longer supported. Instead a slightly improved version is made part of llibs/cardano-ledger-test

A tiny fix that disallows Ptrs in the stake credential of Conway Addresses.

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]

When removing or adding a package or a section in a package we need to run ./scripts/gen-hie.sh, which will make the necessary adjustments.