[FRAME] Short-circuit fungible self transfer (#2118)

Changes:
- Change the fungible(s) logic to treat a self-transfer as No-OP (as
long as all pre-checks pass).

Note that the self-transfer case will not emit an event since no state
was changed.

---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

bridges/primitives/relayers/src/lib.rs

@@ -115,7 +115,7 @@ where
 impl<T, Relayer> PaymentProcedure<Relayer, T::Balance> for PayRewardFromAccount<T, Relayer>
 where
 	T: frame_support::traits::fungible::Mutate<Relayer>,
-	Relayer: Decode + Encode,
+	Relayer: Decode + Encode + Eq,
 {
 	type Error = sp_runtime::DispatchError;