[consensus increase round prober default timeout to 4s (#20862)

## Description 

It should be ok to exclude responses when they are taking >= 2s to
return, for quorum round calculations. But it seems better to use a
longer timeout to reduce variance in the computed quorum rounds among
validators.

## Test plan 

CI

---

## Release notes

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

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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): 
- [ ] gRPC:
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK:

consensus/config/src/parameters.rs

@@ -146,7 +146,7 @@ impl Parameters {
         if cfg!(msim) {
             800
         } else {
-            2000
+            4000
         }
     }
 

consensus/config/tests/snapshots/parameters_test__parameters.snap

@@ -16,7 +16,7 @@ sync_last_known_own_block_timeout:
   secs: 5
   nanos: 0
 round_prober_interval_ms: 5000
-round_prober_request_timeout_ms: 2000
+round_prober_request_timeout_ms: 4000
 propagation_delay_stop_proposal_threshold: 5
 dag_state_cached_rounds: 500
 commit_sync_parallel_fetches: 8