use mtl >=2.3

[larskuhtz]

Switch to mtl >=2.3. This is a prerequisite for supporting sbv-10.

The code changes as well as the update of the sbv pin are due to the following changes:

• mtl modules do not re-export Control.Monad any more
• Either is not an instance of Alternative any more

[to the best of my knowledge nothing of the following applies to this PR]

PR checklist:

• Test coverage for the proposed changes
• PR description contains example output from repl interaction or a snippet from unit test output
• Documentation has been updated if new natives or FV properties have been added. To generate new documentation, issue cabal run tests. If they pass locally, docs are generated.
• Any changes that could be relevant to users have been recorded in the changelog
• In case of changes to the Pact trace output (pact -t), make sure pact-lsp is in sync.

Additionally, please justify why you should or should not do the following:

• Confirm replay/back compat
• Benchmark regressions
• (For Kadena engineers) Run integration-tests against a Chainweb built with this version of Pact