Reduce "Connecting to Echotest" waiting time by 4 seconds

one of the most annoying things about breakout rooms is that the users have to do the echo test again. So they have to wait 7 to 12 seconds again (for most typical bbb configurations) just for the echo test to connect. This change reduces the iceCheckingTimeout from 5 seconds to 1 second, which is still way more than enough unless there is a configuration or network load issue. Depending on network of the used client, this change saves the user between 4 to 8 seconds for every time they activate audio playback or microphone.
The original 5 seconds timeout is not part of the official sip.js library but instead was added in bigbluebutton#2877

bigbluebutton-html5/public/compatibility/sip.js

@@ -9550,7 +9550,7 @@ UA.prototype.loadConfig = function(configuration) {
       userAgentString: SIP.C.USER_AGENT,
 
       // Session parameters
-      iceCheckingTimeout: 5000,
+      iceCheckingTimeout: 1000,
       noAnswerTimeout: 60,
       stunServers: ['stun:stun.l.google.com:19302'],
       turnServers: [],