Share AuthorityHealth information with AuthorityAggregator

[mystenmark]

AuthorityHealth should be shared with AuthorityAggrator in order to better cope with degraded network conditions. See: https://github.com/MystenLabs/sui/blob/main/crates/sui-core/src/authority_active.rs#L72

Todos:

• [ ] AuthorityAggregator::new takes an Arc<AuthorityHealth> arg, which may be owned either by AuthorityActive or GatewayState, depending on the context.
• [ ] AuthorityAggregator methods should be instrumented to update health information in AuthorityHealth.