chore: refactor to use snake_case in proto

[jaeseung-bae]

Description

closes: #XXXX

• Use snake_case in proto

Motivation and context

How has this been tested?

Screenshots (if appropriate):

Checklist:

• [x] I followed the contributing guidelines and code of conduct.
• [x] I have added a relevant changelog to CHANGELOG.md
• [ ] I have added tests to cover my changes.
• [ ] I have updated the documentation accordingly.
• [ ] I have updated API documentation client/docs/swagger-ui/swagger.yaml

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 69.68%. Comparing base (6ca08db) to head (b9dc0d0).

Additional details and impacted files

[](https://app.codecov.io/gh/Finschia/finschia-sdk/pull/1396?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Finschia) ```diff @@ Coverage Diff @@ ## main #1396 +/- ## ======================================= Coverage 69.68% 69.68% ======================================= Files 668 668 Lines 56242 56242 ======================================= Hits 39194 39194 Misses 14775 14775 Partials 2273 2273 ```