Fix cfg.svc bug

Author: aboba

samples/encode-decode-worker/index.html

@@ -66,7 +66,7 @@ <h2>WebCodecs in Worker</h2>
 <div id="rateInput">
   <label for="rate">bitrate: </label>
   <input type="text" name="rate" id="rate"
-      value=2000000>
+      value=1000000>
 </div>
 
 <div id="keyInput">

samples/encode-decode-worker/js/stream_worker.js

@@ -176,7 +176,7 @@ class pipeline {
                controller.enqueue(configChunk); 
              } 
              chunk.temporalLayerId = 0;
-             if (cfg.svc.temporalLayerId) {
+             if (cfg.svc) {
                chunk.temporalLayerId = cfg.svc.temporalLayerId;
              }
              this.seqNo++;