Bump github.com/ava-labs/coreth from 0.13.6-rc.1.0.20240718130554-0110293d1f4b to 0.13.8-fixed-genesis-upgrade

Bump github.com/ava-labs/coreth from 0.13.6-rc.1.0.20240718130554-0110293d1f4b to 0.13.8-fixed-genesis-upgrade #14