fix(live-streaming): trim the entered stream key

react/features/recording/components/LiveStream/AbstractStartLiveStreamDialog.js

      */
     _onSubmit() {
         const { broadcasts, selectedBoundStreamID } = this.state;
-        const key = this.state.streamKey || this.props._streamKey;
+        const key
+            = (this.state.streamKey || this.props._streamKey || '').trim();
 
         if (!key) {
             return false;