feat(l1): omit copying bytes when encoding transactions (#5137)

**Motivation**
When encoding non-legacy transactions we need to encode the payload
(txType || rlp(Transaction) as a bytes object. In order to do so we copy
the payload to a `Bytes` object and then encode it in rlp, this is not
needed as we can just encode the payload as bytes by invoking the
implementation for [u8] directly

**Description**
* Avoid using `Bytes::copy_from_slice` when encoding transactions
<!-- A clear and concise general description of the changes this PR
introduces -->

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

Author: fmoletta

crates/common/types/transaction.rs

@@ -70,7 +70,7 @@ impl RLPEncode for P2PTransaction {
     fn encode(&self, buf: &mut dyn bytes::BufMut) {
         match self {
             P2PTransaction::LegacyTransaction(t) => t.encode(buf),
-            tx => Bytes::copy_from_slice(&tx.encode_canonical_to_vec()).encode(buf),
+            tx => <[u8] as RLPEncode>::encode(&tx.encode_canonical_to_vec(), buf),
         };
     }
 }
@@ -395,7 +395,7 @@ impl RLPEncode for Transaction {
     fn encode(&self, buf: &mut dyn bytes::BufMut) {
         match self {
             Transaction::LegacyTransaction(t) => t.encode(buf),
-            tx => Bytes::copy_from_slice(&tx.encode_canonical_to_vec()).encode(buf),
+            tx => <[u8] as RLPEncode>::encode(&tx.encode_canonical_to_vec(), buf),
         };
     }
 }