Add fixup combinators to ImpTest framework

[teodanciu]

Description

Resolves #4209

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

[Soupstraw]

Awesome, even better than what I had in mind!

[lehins]

This looks great! I have even a follow up idea how we can make it even better:

Let's get rid of iteDoTxFixup and itePostFixup in favor of one: iteFixup :: Tx era -> ImpTestM era (Tx era)

For times when no fixup is necessary we can just use pure, while by default in the runImpTestM we can use fixupTx.

Then withPostFixup will become a composition of the current fixup function that is currently set in iteFixup and the one that is supplied as an argument.

@Soupstraw what are your thoughts on this subject? Asking you since you really advocated for a boolean flag.

[Soupstraw]

Let's get rid of iteDoTxFixup and itePostFixup in favor of one: iteFixup :: Tx era -> ImpTestM era (Tx era)

@lehins I like that idea, it's a more flexible version of what we have right now. We can still keep the withNoFixup combinator around for convenience, just make it set the fixup function to pure.

[teodanciu]

I pushed some changes that I believe implement what @lehins 's suggestion was .

I have doubts about how this will be used!
So:

• for no fixup at all: withNoFixup - as before
• for "auto fixup" and extra things: withPostFixup
• for only extra things, we'll have to do: withPostFixup (\f -> withNoFixup ( ..)
  Isn't it kinda clunky ? I have looked at this too much to have an objective view, so happy to go with it if you think so. @lehins @Soupstraw

[lehins]

Looks great! One tiny mistake and a suggestion

[lehins]

Awesome!