1k block chunk for scroll indexing (#2956)

### Description

RPC URLs on scroll max out at 1k

### Drive-by changes

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### Related issues

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- Fixes #[issue number here]
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### Backward compatibility

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### Testing

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rust/config/mainnet3_config.json

@@ -625,7 +625,8 @@
       "mailbox": "0x2f2aFaE1139Ce54feFC03593FeE8AB2aDF4a85A7",
       "validatorAnnounce": "0xd83A4F747fE80Ed98839e05079B1B7Fe037b1638",
       "index": {
-        "from": 426670
+        "from": 426670,
+        "chunk": 999
       }
     }
   },