improvement(client-presence): make events private (microsoft#23029)

as no one should need access.

packages/framework/presence/src/systemWorkspace.ts

@@ -111,7 +111,7 @@ class SystemWorkspaceImpl implements PresenceStatesInternal, SystemWorkspace {
 	public constructor(
 		clientSessionId: ClientSessionId,
 		private readonly datastore: SystemWorkspaceDatastore,
-		public readonly events: IEmitter<
+		private readonly events: IEmitter<
 			Pick<PresenceEvents, "attendeeJoined" | "attendeeDisconnected">
 		>,
 	) {