Fix: hydra CI error when allow lint attribute specifies a reason

[dlachaume]

Content

This PR fix an error detailed in the draft issue.

The linting reason has been removed, as it's still experimental and cannot be applied yet.

The initial error from Hydra CI: https://github.com/input-output-hk/mithril/pull/1948/checks?check_run_id=30529857732

error[E0658]: lint reasons are experimental
  --> mithril-common/src/logging.rs:31:9
   |
31 |         reason = "A field is needed to add the lifetime but is unused"
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #54503 <https://github.com/rust-lang/rust/issues/54503> for more information

Pre-submit checklist

• Branch
  • Crates versions are updated (if relevant)
  • Commit sequence broadly makes sense
  • Key commits have useful messages
• PR
  • No clippy warnings in the CI
  • Self-reviewed the diff
  • Useful pull request description
  • Reviewer requested

[github-actions]

Test Results

    4 files  ±0     54 suites  ±0   9m 36s ⏱️ -1s
1 299 tests ±0  1 299 ✅ ±0  0 💤 ±0  0 ❌ ±0 
1 510 runs  ±0  1 510 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 69fc137. ± Comparison against base commit e4e7404.

♻️ This comment has been updated with latest results.