fix: flaky e2e-p2p test (AztecProtocol#3831)

Fixes AztecProtocol#3654

**Note**: Lasse had a good hunch that it's most likely caused by
different nodes using the same l1 publisher private key. This PR changes
this and uses different accounts for different nodes. I am quite
confident that that is the culprit so I will close the issue.

Author: benesjan

yarn-project/end-to-end/src/e2e_p2p_network.test.ts

@@ -17,8 +17,13 @@ import { TestContractArtifact } from '@aztec/noir-contracts/Test';
 import { BootstrapNode, P2PConfig, createLibP2PPeerId } from '@aztec/p2p';
 import { ConstantKeyPair, PXEService, createPXEService, getPXEServiceConfig as getRpcConfig } from '@aztec/pxe';
 
+import { mnemonicToAccount } from 'viem/accounts';
+
+import { MNEMONIC } from './fixtures/fixtures.js';
 import { setup } from './fixtures/utils.js';
 
+// Don't set this to a higher value than 9 because each node will use a different L1 publisher account and anvil seeds
+// only 10 accounts with ETH (9 and not 10 because first account is used by sandbox).
 const NUM_NODES = 4;
 const NUM_TXS_PER_BLOCK = 4;
 const NUM_TXS_PER_NODE = 2;
@@ -55,7 +60,7 @@ describe('e2e_p2p_network', () => {
     // is if the txs are successfully gossiped around the nodes.
     const contexts: NodeContext[] = [];
     for (let i = 0; i < NUM_NODES; i++) {
-      const node = await createNode(i + 1 + BOOT_NODE_TCP_PORT, bootstrapNodeAddress);
+      const node = await createNode(i + 1 + BOOT_NODE_TCP_PORT, bootstrapNodeAddress, i);
       const context = await createPXEServiceAndSubmitTransactions(node, NUM_TXS_PER_NODE);
       contexts.push(context);
     }
@@ -107,7 +112,13 @@ describe('e2e_p2p_network', () => {
   };
 
   // creates a P2P enabled instance of Aztec Node Service
-  const createNode = async (tcpListenPort: number, bootstrapNode: string) => {
+  const createNode = async (tcpListenPort: number, bootstrapNode: string, publisherAddressIndex: number) => {
+    // We use different L1 publisher accounts in order to avoid duplicate tx nonces. We start from
+    // publisherAddressIndex + 1 because index 0 was already used during sandbox setup.
+    const hdAccount = mnemonicToAccount(MNEMONIC, { addressIndex: publisherAddressIndex + 1 });
+    const publisherPrivKey = Buffer.from(hdAccount.getHdKey().privateKey!);
+    config.publisherPrivateKey = `0x${publisherPrivKey!.toString('hex')}`;
+
     const newConfig: AztecNodeConfig = {
       ...config,
       tcpListenPort,