feat(tx-sender): Limit concurrent tx submissions (#1473)

## What ❔

Limits tx submissions in a way that at most one tx per (address, nonce)
can be inserted into DB at any given moment.

## Why ❔

Database poorly handles concurrent tx insertions

## Checklist

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<!-- 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/lib/dal/src/blocks_web3_dal.rs

@@ -863,7 +863,8 @@ mod tests {
         for (i, tx) in transactions.into_iter().enumerate() {
             conn.transactions_dal()
                 .insert_transaction_l2(tx.clone(), TransactionExecutionMetrics::default())
-                .await;
+                .await
+                .unwrap();
             let mut tx_result = mock_execution_result(tx);
             tx_result.call_traces.push(Call {
                 from: Address::from_low_u64_be(i as u64),

core/lib/dal/src/sync_dal.rs

@@ -165,7 +165,8 @@ mod tests {
         let tx = mock_l2_transaction();
         conn.transactions_dal()
             .insert_transaction_l2(tx.clone(), TransactionExecutionMetrics::default())
-            .await;
+            .await
+            .unwrap();
         conn.blocks_dal()
             .insert_miniblock(&miniblock_header)
             .await

core/lib/dal/src/tests/mod.rs

@@ -172,13 +172,15 @@ async fn workflow_with_submit_tx_equal_hashes() {
     let tx = mock_l2_transaction();
     let result = transactions_dal
         .insert_transaction_l2(tx.clone(), mock_tx_execution_metrics())
-        .await;
+        .await
+        .unwrap();
 
     assert_eq!(result, L2TxSubmissionResult::Added);
 
     let result = transactions_dal
         .insert_transaction_l2(tx, mock_tx_execution_metrics())
-        .await;
+        .await
+        .unwrap();
 
     assert_eq!(result, L2TxSubmissionResult::Duplicate);
 }
@@ -196,7 +198,8 @@ async fn workflow_with_submit_tx_diff_hashes() {
 
     let result = transactions_dal
         .insert_transaction_l2(tx, mock_tx_execution_metrics())
-        .await;
+        .await
+        .unwrap();
 
     assert_eq!(result, L2TxSubmissionResult::Added);
 
@@ -205,7 +208,8 @@ async fn workflow_with_submit_tx_diff_hashes() {
     tx.common_data.initiator_address = initiator_address;
     let result = transactions_dal
         .insert_transaction_l2(tx, mock_tx_execution_metrics())
-        .await;
+        .await
+        .unwrap();
 
     assert_eq!(result, L2TxSubmissionResult::Replaced);
 }
@@ -227,12 +231,14 @@ async fn remove_stuck_txs() {
     tx.received_timestamp_ms = unix_timestamp_ms() - Duration::new(1000, 0).as_millis() as u64;
     transactions_dal
         .insert_transaction_l2(tx, mock_tx_execution_metrics())
-        .await;
+        .await
+        .unwrap();
     // Tx in mempool
     let tx = mock_l2_transaction();
     transactions_dal
         .insert_transaction_l2(tx, mock_tx_execution_metrics())
-        .await;
+        .await
+        .unwrap();
 
     // Stuck L1 tx. We should never ever remove L1 tx
     let mut tx = mock_l1_execute();
@@ -247,7 +253,8 @@ async fn remove_stuck_txs() {
         unix_timestamp_ms() - Duration::new(1000, 0).as_millis() as u64;
     transactions_dal
         .insert_transaction_l2(executed_tx.clone(), mock_tx_execution_metrics())
-        .await;
+        .await
+        .unwrap();
 
     // Get all txs
     transactions_dal.reset_mempool().await.unwrap();