fix(prover): Reduce database connection overhead for BWG (#2543)

BWG uses connection as part of it's save/update_database cycle. This
means that every execute call is sent to the database. Transaction can
be used to "batch" those and be sent only during commit.

This will get rid of 10 minutes on mainnet (on worst batches).

prover/crates/bin/witness_generator/src/basic_circuits.rs

@@ -291,12 +291,19 @@ async fn update_database(
     block_number: L1BatchNumber,
     blob_urls: BlobUrls,
 ) {
-    let mut prover_connection = prover_connection_pool.connection().await.unwrap();
-    let protocol_version_id = prover_connection
+    let mut connection = prover_connection_pool
+        .connection()
+        .await
+        .expect("failed to get database connection");
+    let mut transaction = connection
+        .start_transaction()
+        .await
+        .expect("failed to get database transaction");
+    let protocol_version_id = transaction
         .fri_witness_generator_dal()
         .protocol_version_for_l1_batch(block_number)
         .await;
-    prover_connection
+    transaction
         .fri_prover_jobs_dal()
         .insert_prover_jobs(
             block_number,
@@ -306,7 +313,7 @@ async fn update_database(
             protocol_version_id,
         )
         .await;
-    prover_connection
+    transaction
         .fri_witness_generator_dal()
         .create_aggregation_jobs(
             block_number,
@@ -316,10 +323,14 @@ async fn update_database(
             protocol_version_id,
         )
         .await;
-    prover_connection
+    transaction
         .fri_witness_generator_dal()
         .mark_witness_job_as_successful(block_number, started_at.elapsed())
         .await;
+    transaction
+        .commit()
+        .await
+        .expect("failed to commit database transaction");
 }
 
 #[tracing::instrument(skip_all, fields(l1_batch = %block_number))]