clean up unused sui errors and delete AuthorityNotifier (MystenLabs#8641

)

## Description 

This PR cleans up unused SuiErrors and AuthorityNotifier.

## Test Plan 

lint

---
If your changes are not user-facing and not a breaking change, you can
skip the following section. Otherwise, please indicate what changed, and
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### Type of Change (Check all that apply)

- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes
Clean up unused SuiErrors and AuthorityNotifier.