fix(BridgeChannel): Attempt conn retries when there are remote endpoints.

Currently, the client doesn't attempt to re-establish bridge WS when the connection is closed by the remote end with a code 1001. We have noticed that Cloudflare terminates the WS with the same error code when it recycles its proxies. When that happens, client ends up not having a bridge channel which can result quality issues.
Client now tries to re-establish connection when there are remote endpoints in the call.

modules/RTC/BridgeChannel.js

      * instance.
      * @param {string} [wsUrl] WebSocket URL.
      * @param {EventEmitter} emitter the EventEmitter instance to use for event emission.
+     * @param {JitsiConference} conference the conference instance.
      */
-    constructor(peerconnection, wsUrl, emitter) {
+    constructor(peerconnection, wsUrl, emitter, conference) {
         if (!peerconnection && !wsUrl) {
             throw new TypeError('At least peerconnection or wsUrl must be given');
         } else if (peerconnection && wsUrl) {
         // @type {RTCDataChannel|WebSocket}
         this._channel = null;
 
+        // The conference that uses this bridge channel.
+        this._conference = conference;
+
         // Whether the channel is connected or not. It will start as undefined
         // for the first connection attempt. Then transition to either true or false.
         this._connected = undefined;
                 return;
             }
 
-            // When the JVB closes the connection gracefully due to the participant being alone in
-            // the meeting it uses code 1001, so treat that as a graceful close and don't say
-            // anything.
-            const isGracefulClose = this._closedFromClient || event.code === 1001;
+            // When the JVB closes the connection gracefully due to the participant being alone in the meeting it uses
+            // code 1001. However, the same code is also used by Cloudflare when it terminates the ws. Therefore, check
+            // for the number of remote participants in the call and abort retries only when the endpoint is the only
+            // endpoint in the call.
+            const isGracefulClose = this._closedFromClient
+                || (event.code === 1001 && this._conference.getParticipantCount() === 1);
 
             if (!isGracefulClose) {
                 const { code, reason } = event;

modules/RTC/RTC.js

      * @param {string} [wsUrl] WebSocket URL.
      */
     initializeBridgeChannel(peerconnection, wsUrl) {
-        this._channel = new BridgeChannel(peerconnection, wsUrl, this.eventEmitter);
+        this._channel = new BridgeChannel(peerconnection, wsUrl, this.eventEmitter, this.conference);
 
         this._channelOpenListener = () => {
             const logError = (error, msgType, value) => {