Remove manual workflow step for old `snapshot` commands availability

[dlachaume]

Content

This PR includes a fix for the manual workflow Mithril Client multi-platform test that removes command compatibility steps due to the removal of the snapshot command.

Pre-submit checklist

• Branch
  • [ ] Tests are provided (if possible)
  • [ ] Crates versions are updated (if relevant)
  • [ ] CHANGELOG file is updated (if relevant)
  • [x] Commit sequence broadly makes sense
  • [x] Key commits have useful messages
• PR
  • [x] No clippy warnings in the CI
  • [x] Self-reviewed the diff
  • [x] Useful pull request description
  • [x] Reviewer requested
• Documentation
  • [ ] Update README file (if relevant)
  • [ ] Update documentation website (if relevant)
  • [ ] Add dev blog post (if relevant)

[github-actions[bot]]

Test Results

    3 files  ±0     43 suites  ±0   8m 45s :stopwatch: +18s 1 012 tests ±0  1 012 :white_check_mark: ±0  0 :zzz: ±0  0 :x: ±0  1 110 runs  ±0  1 110 :white_check_mark: ±0  0 :zzz: ±0  0 :x: ±0 

Results for commit d0876fb6. ± Comparison against base commit 665621d3.