Test DRep retirement in an integration test

[smelc]

Description

This PR adds an integration test that deregistering a DRep has the desired effect on the ledger state.

This new tests runs approximately in 55 seconds and does not use foldBlocks, but uses checkLedgerStateCondition instead 💪

Context

Fixes #5596

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added
• NA Any changes are noted in the CHANGELOG.md for affected package
• NA The version bounds in .cabal files are updated
• CI passes. See note on CI. The following CI checks are required:
• Self-reviewed the diff

[smelc]

Convert to draft, as we want to use a ledger event instead of a timeout, as agreed today during the team's weekly. The event needs to be added to cardano-ledger.

[smelc]

Reminder to myself: use #5664 when it's merged to read the drep-state.

[Jimbo4350]

LGTM! Couple comments.