fix: use path-only dependency for testing utils

[MegaRedHand]

Fixes #

What Changed?

This PR fixes the cargo publish error we got on previous releases (run logs here):

  2025-02-06T14:09:32.528381Z ERROR  failed to release package

Caused by:
    failed to publish eigen-crypto-bls:     Updating crates.io index
    error: all dependencies must have a version specified when publishing.
    dependency `eigen-crypto-bn254` does not specify a version
    Note: The published dependency will use the version from crates.io,
    the `path` specification will be removed from the dependency declaration.

This error was due to some crates having cyclic dev-dependencies. We fix those by removing the version from the dev-dependency, leaving the path only, as specified in this issue: rust-lang/cargo#4242 (comment).

Reviewer Checklist

• New features are tested and documented
• PR updates the changelog with a description of changes
• PR has one of the changelog-X labels (if applies)
• Code deprecates any old functionality before removing it