fix(l1): wait before retring on error in dev's block producer (#5391)

**Motivation**

<!-- Why does this pull request exist? What are its goals? -->
There was a race condition where dev's block producer starts before the
RPC. In this scenario, the block producer tries to make some requests to
the Engine API, failing three times in a row and thus ending.

**Description**

<!-- A clear and concise general description of the changes this PR
introduces -->
Add a small delay between retries so Engine RPC has time to get up

<!-- Link to issues: Resolves #111, Resolves #222 -->

Co-authored-by: Ivan Litteri <67517699+ilitteri@users.noreply.github.com>

Author: ManuelBilbao

crates/blockchain/dev/block_producer.rs

@@ -4,6 +4,7 @@ use ethrex_rpc::clients::{EngineClient, EngineClientError};
 use ethrex_rpc::types::fork_choice::{ForkChoiceState, PayloadAttributesV3};
 use sha2::{Digest, Sha256};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
+use tokio::time::sleep;
 
 pub async fn start_block_producer(
     execution_client_auth_url: String,
@@ -51,6 +52,7 @@ pub async fn start_block_producer(
                 tracing::error!(
                     "Failed to produce block: error sending engine_forkchoiceUpdatedV3 with PayloadAttributes: {error}"
                 );
+                sleep(Duration::from_millis(300)).await;
                 tries += 1;
                 continue;
             }
@@ -73,6 +75,7 @@ pub async fn start_block_producer(
                 tracing::error!(
                     "Failed to produce block: error sending engine_getPayloadV5: {error}"
                 );
+                sleep(Duration::from_millis(300)).await;
                 tries += 1;
                 continue;
             }
@@ -106,6 +109,7 @@ pub async fn start_block_producer(
                 tracing::error!(
                     "Failed to produce block: error sending engine_newPayloadV4: {error}"
                 );
+                sleep(Duration::from_millis(300)).await;
                 tries += 1;
                 continue;
             }
@@ -117,6 +121,7 @@ pub async fn start_block_producer(
             tracing::error!(
                 "Failed to produce block: latest_valid_hash is None in PayloadStatus: {payload_status:?}"
             );
+            sleep(Duration::from_millis(300)).await;
             tries += 1;
             continue;
         };