fix: add --rpc.eth-proof-window flag to reth (#1390)

When using reth via reth-rbuilder, add the `--rpc.eth-proof-window` flag
to avoid the following errors when running block simulation
```
block is too old, outside validation window
```

Author: bharath-123

src/el/reth/reth_launcher.star

@@ -296,6 +296,7 @@ def get_config(
         cmd.append(
             "--txpool.no-local-transactions-propagation"
         )  # disable tx propagation so that builder will have juicy blocks
+        cmd.append("--rpc.eth-proof-window=3")
         files[
             flashbots_rbuilder.MEV_BUILDER_MOUNT_DIRPATH_ON_SERVICE
         ] = flashbots_rbuilder.MEV_BUILDER_FILES_ARTIFACT_NAME