Cardano Updates

# Description

This PR adds "eligible voters" metric to the snapshot importer logs as
being the amount of wallets able to vote.

## How Has This Been Tested?

Executed the voting node + snapshot importer locally.

## Checklist

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules