refactor(presence): route stream-user-presence subscribe through DDPSDK when ready

The stream-user-presence 'subscription' is used as a fire-and-forget
command channel: each call hands the server an added/removed list of
user ids and the server keeps its own tracking; the client never calls
stop(). Same behaviour applies when we route it through DDPSDK instead
of Meteor.subscribe, so wrap the call in a helper that picks
ddpSdk.client.subscribe while the SDK is authenticated and falls back
to Meteor.subscribe otherwise.

Author: ggazzo

apps/meteor/client/lib/presence.ts

@@ -5,6 +5,19 @@ import { Emitter } from '@rocket.chat/emitter';
 import { Meteor } from 'meteor/meteor';
 
 import { sdk } from '../../app/utils/client/lib/SDKClient';
+import { getDdpSdk } from './sdk/ddpSdk';
+
+const subscribeUserPresence = (payload: { added?: string[]; removed?: string[] }): void => {
+	const ddp = getDdpSdk();
+	if (ddp.connection.status === 'connected' && ddp.account.uid) {
+		// Fire the command-style subscription over our SDK; it has no lifecycle
+		// (the server registers the added/removed uids and moves on), matching
+		// Meteor.subscribe's behaviour here.
+		ddp.client.subscribe('stream-user-presence', '', payload);
+		return;
+	}
+	Meteor.subscribe('stream-user-presence', '', payload);
+};
 
 type InternalEvents = {
 	remove: IUser['_id'];
@@ -55,7 +68,7 @@ const getPresence = ((): ((uid: UserPresence['_id']) => void) => {
 			const ids = Array.from(currentUids);
 			const removed = Array.from(deletedUids);
 
-			Meteor.subscribe('stream-user-presence', '', {
+			subscribeUserPresence({
 				...(ids.length > 0 && { added: Array.from(currentUids) }),
 				...(removed.length && { removed: Array.from(deletedUids) }),
 			});