## Description 

This PR moves the construction of AuthorityAggregator to sui-node and
stores a reference there.
This will make sure that all the metrics are ever only instantiated once
(to avoid double register problem).
It will also allow us to use AuthorityAggregator later in
ValidatorTxFinalizer.

## Test plan 

CI

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## Release notes

Check each box that your changes affect. If none of the boxes relate to
your changes, release notes aren't required.

For each box you select, include information after the relevant heading
that describes the impact of your changes that a user might notice and
any actions they must take to implement updates.

- [ ] Protocol: 
- [ ] Nodes (Validators and Full nodes): 
- [ ] Indexer: 
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK: