Fix ability to launch a console from the launcher

src/console/plugin.ts

@@ -210,6 +210,8 @@ function activateConsole(app: JupyterLab, services: IServiceManager, rendermime:
   command = 'console:create';
   commands.addCommand(command, {
     execute: (args: ICreateConsoleArgs) => {
+      args = args || {};
+
       let name = `Console ${++count}`;
 
       // If we get a session, use it.

src/landing/plugin.ts

@@ -95,7 +95,7 @@ function activateLanding(app: JupyterLab, services: IServiceManager, pathTracker
 
   img = body.getElementsByClassName('jp-ImageCodeConsole')[0];
   img.addEventListener('click', () => {
-    app.commands.execute(`console:create-${services.kernelspecs.default}`, void 0);
+    app.commands.execute('console:create', void 0);
   });
 
   img = body.getElementsByClassName('jp-ImageTextEditor')[0];