[PERFORMANCE FIX] rollback two additional metrics

[mgmeier]

Description

This PR presumably fixes a performance regression that was introduced by adding two Conway-exclusive metrics to the new tracing system.

Tracing those metrics will need a minor redesign wrt. the code location the trace is emitted. The current location exerts too much pressure on an STM value that's on the hot code path in the forging loop - which leads to the observed regression.

Till then, introduction of those two new metrics is rolled back.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. These may include:
  • golden tests
  • property tests
  • roundtrip tests
  • integration tests
    See Runnings tests for more details
• Any changes are noted in the CHANGELOG.md for affected package
• The version bounds in .cabal files are updated
• CI passes. See note on CI. The following CI checks are required:
  • Code is linted with hlint. See .github/workflows/check-hlint.yml to get the hlint version
  • Code is formatted with stylish-haskell. See .github/workflows/stylish-haskell.yml to get the stylish-haskell version
  • Code builds on Linux, MacOS and Windows for ghc-8.10.7 and ghc-9.2.7
• Self-reviewed the diff

[jutaro]

LGTM

[NadiaYvette]

This looks like a straightforward backout.