Always persist the ChannelManager on a failed ChannelUpdate

If we receive a `ChannelUpdate` message which was invalid, it can
cause us to force-close the channel, which should result in a
`ChannelManager` persistence, though its not critical to do so.

Author: TheBlueMatt

lightning/src/ln/channelmanager.rs

@@ -7668,7 +7668,7 @@ where
 			if let Ok(persist) = handle_error!(self, self.internal_channel_update(counterparty_node_id, msg), *counterparty_node_id) {
 				persist
 			} else {
-				NotifyOption::SkipPersistNoEvents
+				NotifyOption::DoPersist
 			}
 		});
 	}