eth/filters: send rpctransactions in pending-subscription (#26126)

This PR changes the pending tx subscription to return RPCTransaction types instead of normal Transaction objects. This will fix the inconsistencies with other tx returning API methods (i.e. getTransactionByHash), and also fill in the sender value for the tx.

co-authored by @s1na

accounts/abi/bind/backends/simulated.go

@@ -915,6 +915,14 @@ func (fb *filterBackend) ServiceFilter(ctx context.Context, ms *bloombits.Matche
 	panic("not supported")
 }
 
+func (fb *filterBackend) ChainConfig() *params.ChainConfig {
+	panic("not supported")
+}
+
+func (fb *filterBackend) CurrentHeader() *types.Header {
+	panic("not supported")
+}
+
 func nullSubscription() event.Subscription {
 	return event.NewSubscription(func(quit <-chan struct{}) error {
 		<-quit