## Description 

This PR swaps the use of the `build_dag` method with the `DagBuilder` in
the `linearizer, commit_observer and dag_state`

## Test plan 

CI

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## Release notes

Check each box that your changes affect. If none of the boxes relate to
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any actions they must take to implement updates.

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