The executable should be added to "Command" if "launcherId" is set

Scenario:

1. Open "External Tools" tab in the "Application Settings" dialog.
2. In the "Custom tools" group add a tool with a valid "launcherId" parameter (note that there are 4 supported launchers for tools - python, java, R and perl).
3. Open the Workflow Designer.
4. Open the "Create Element with External Tool" wizard.
5. Select the added tool for the element.
6. Follow the wizard until the "Command" page.
   Expected result: the launcher variable is also specified in the command, e.g.:

   %UGENE_PYTHON2% %MY_TOOL_ID% ...