Remove 'try the app' link from login

Fixes https://github.com/vector-im/riot-web/issues/8384

This will be re-addressed in https://github.com/vector-im/riot-web/issues/9388 or similar. Because the implementation is undefined, the dead code is being removed instead of just left dead.

src/components/structures/MatrixChat.js

@@ -2032,7 +2032,6 @@ export default React.createClass({
                     fallbackHsUrl={this.getFallbackHsUrl()}
                     defaultDeviceDisplayName={this.props.defaultDeviceDisplayName}
                     onForgotPasswordClick={this.onForgotPasswordClick}
-                    enableGuest={this.props.enableGuest}
                     onServerConfigChange={this.onServerConfigChange}
                 />
             );