Fix enacted Set in GovInfoEvent

[lehins]

Description

Fix #4602

Besides the fix to GovInfoEvent this PR also:

• Reduced duplication by consolidating to one implementation for generating uniform sub-Map and the same for uniform sub-Set. Three alternative implementations have been removed
• Fixes implementation of uniformSubset. It had a really dumb bug (CC @neilmayhew see if you can spot this bug that I made in a very similar funciton 😄)

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• 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)
• 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)
• 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

[teodanciu]

Looks good to me, just some questions and minor suggestions.