feat(consensus): TxEnvelope::signature (#1634)

* feat(consensus): `TxEnvelope::signature`

* const

crates/consensus/src/transaction/envelope.rs

@@ -9,7 +9,7 @@ use alloy_eips::{
     eip2718::{Decodable2718, Eip2718Error, Eip2718Result, Encodable2718},
     eip2930::AccessList,
 };
-use alloy_primitives::{Bytes, TxKind, B256};
+use alloy_primitives::{Bytes, PrimitiveSignature as Signature, TxKind, B256};
 use alloy_rlp::{Decodable, Encodable};
 use core::fmt;
 
@@ -272,6 +272,17 @@ impl TxEnvelope {
         }
     }
 
+    /// Return the reference to signature.
+    pub const fn signature(&self) -> &Signature {
+        match self {
+            Self::Legacy(tx) => tx.signature(),
+            Self::Eip2930(tx) => tx.signature(),
+            Self::Eip1559(tx) => tx.signature(),
+            Self::Eip4844(tx) => tx.signature(),
+            Self::Eip7702(tx) => tx.signature(),
+        }
+    }
+
     /// Return the hash of the inner Signed.
     #[doc(alias = "transaction_hash")]
     pub const fn tx_hash(&self) -> &B256 {