fix(conference) handle joining another meeting while in one

This can happen when "token auth URL" mode is used since the app will be
redirected to the same meeting it's in, but with a token.

app/features/conference/components/Conference.js

@@ -149,6 +149,21 @@ class Conference extends Component<Props, State> {
         }
     }
 
+    /**
+     * Handle joining another another meeing while in one.
+     *
+     * @param {Object} prevProps - The previous props.
+     * @returns {void}
+     */
+    componentDidUpdate(prevProps) {
+        if (prevProps.location.key !== this.props.location.key) {
+
+            // Simulate a re-mount so the new meeting is joined.
+            this.componentWillUnmount();
+            this.componentDidMount();
+        }
+    }
+
     /**
      * Implements React's {@link Component#render()}.
      *