put the validate_unsigned implementation inside the pallet definition (#9044)

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

substrate/frame/babe/src/lib.rs

@@ -407,6 +407,18 @@ pub mod pallet {
 			Ok(())
 		}
 	}
+
+	#[pallet::validate_unsigned]
+	impl<T: Config> ValidateUnsigned for Pallet<T> {
+		type Call = Call<T>;
+		fn validate_unsigned(source: TransactionSource, call: &Self::Call) -> TransactionValidity {
+			Self::validate_unsigned(source, call)
+		}
+
+		fn pre_dispatch(call: &Self::Call) -> Result<(), TransactionValidityError> {
+			Self::pre_dispatch(call)
+		}
+	}
 }
 
 /// A BABE public key