Delayed block production on builder flow

### Describe the bug

After `mev-boost` returns execution payload, it took ~1.5s to compute state root

```
Jun-03 22:01:24.079[chain] ^[[36mverbose^[[39m: Produced beacon block body fork=deneb, blockType=Blinded, slot=9219005, attestations=128, deposits=0, voluntaryExits=0, attesterSlashings=0, proposerSlashings=0, feeRecipientType=cached, feeRecipient=0x388c818ca8b9251b393131c08a736a67ccb19297, blobs=6, blsToExecutionChanges=0, executionPayloadValue=119928262811004670
Jun-03 22:01:25.514[chain] ^[[34mdebug^[[39m: Computing block post state from the produced body slot=9219005, bodyRoot=0xbd6173928e590b3f279d3647fbfcd22c0c57112fa0f2962da7ae9d934ea45b5e, blockType=Blinded
```

### Expected behavior

Need to figure out which action caused time there (no log between the two), can we improve or add more metrics if needed. Note that there is execution block being produced at the same time

### Steps to reproduce

_No response_

### Additional context

_No response_

### Operating system

Linux

### Lodestar version or commit hash

v1.18.1