Treat all signal messages as ping response (#933)

* Treat all signal messages as ping

In cases of rooms that are highly active, it's possible to have a lot of
signal messages queued that it blocks the ping messages for awhile.

Since the purpose of ping/pong is to ensure signal channel is active, it
makes sense to use any type of signal traffic as that indicator of liveliness.

* changeset

.changeset/healthy-pillows-own.md

@@ -0,0 +1,5 @@
+---
+'livekit-client': patch
+---
+
+Treat all signal messages as ping response

src/api/SignalClient.ts

@@ -558,6 +558,8 @@ export class SignalClient {
       log.debug('received unsupported message');
       return;
     }
+
+    let pingHandled = false;
     if (msg.case === 'answer') {
       const sd = fromProtoSessionDescription(msg.value);
       if (this.onAnswer) {
@@ -626,13 +628,17 @@ export class SignalClient {
         this.onSubscriptionError(msg.value);
       }
     } else if (msg.case === 'pong') {
-      this.resetPingTimeout();
     } else if (msg.case === 'pongResp') {
       this.rtt = Date.now() - Number.parseInt(msg.value.lastPingTimestamp.toString());
       this.resetPingTimeout();
+      pingHandled = true;
     } else {
       log.debug('unsupported message', msg);
     }
+
+    if (!pingHandled) {
+      this.resetPingTimeout();
+    }
   }
 
   setReconnected() {