Add SessionStaticSecret::to_bytes but only with test vector feature flag

Author: cygnusv

nucypher-core/src/dkg.rs

@@ -294,6 +294,15 @@ pub mod session {
             let public_key = PublicKey::from(&self.0);
             SessionStaticKey(public_key)
         }
+
+        #[cfg(feature = "test_vectors")]
+        /// Returns the raw bytes of the secret key.
+        /// 
+        /// This function is only available when the `test_vectors` feature is enabled.
+        /// It should only be used for test vector generation and not in production code.
+        pub fn to_bytes(&self) -> [u8; 32] {
+            self.0.to_bytes()
+        }
     }
 
     impl fmt::Display for SessionStaticSecret {