CHANGELOG: remove frontend leaderboard

Author: dannywillems

CHANGELOG.md

@@ -125,6 +125,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#1577](https://github.com/o1-labs/mina-rust/pull/1577))
 - **tools**: remove producer-dashboard
   ([#1578](https://github.com/o1-labs/mina-rust/pull/1578))
+- **frontend**: remove leaderboard from the frontend
+  ([#1579](https://github.com/o1-labs/mina-rust/pull/1579)
 
 ## v0.17.0