fix(node_framework): Fix main node example (#1470)

## What ❔

Adds missing layer that prevented main node example from running

## Why ❔

Main node example works now.

## Checklist

<!-- Check your PR fulfills the following items. -->
<!-- For draft PRs check the boxes as you complete them. -->

- [ ] PR title corresponds to the body of PR (we generate changelog
entries from PRs).
- [ ] Tests for the changes have been added / updated.
- [ ] Documentation comments have been added / updated.
- [ ] Code has been formatted via `zk fmt` and `zk lint`.
- [ ] Spellcheck has been run via `zk spellcheck`.
- [ ] Linkcheck has been run via `zk linkcheck`.

core/node/node_framework/examples/main_node.rs

@@ -32,6 +32,7 @@ use zksync_node_framework::{
         l1_gas::SequencerL1GasLayer,
         metadata_calculator::MetadataCalculatorLayer,
         object_store::ObjectStoreLayer,
+        pk_signing_eth_client::PKSigningEthClientLayer,
         pools_layer::PoolsLayerBuilder,
         proof_data_handler::ProofDataHandlerLayer,
         query_eth_client::QueryEthClientLayer,
@@ -71,6 +72,15 @@ impl MainNodeBuilder {
         Ok(self)
     }
 
+    fn add_pk_signing_client_layer(mut self) -> anyhow::Result<Self> {
+        self.node.add_layer(PKSigningEthClientLayer::new(
+            ETHSenderConfig::from_env()?,
+            ContractsConfig::from_env()?,
+            ETHClientConfig::from_env()?,
+        ));
+        Ok(self)
+    }
+
     fn add_query_eth_client_layer(mut self) -> anyhow::Result<Self> {
         let eth_client_config = ETHClientConfig::from_env()?;
         let query_eth_client_layer = QueryEthClientLayer::new(eth_client_config.web3_url);
@@ -306,6 +316,7 @@ fn main() -> anyhow::Result<()> {
         .add_metadata_calculator_layer()?
         .add_state_keeper_layer()?
         .add_eth_watch_layer()?
+        .add_pk_signing_client_layer()?
         .add_eth_sender_layer()?
         .add_proof_data_handler_layer()?
         .add_healthcheck_layer()?