test(AddComponentButtonComponent): Improve test

[geoffreykwan]

The test in add-component-button.component.spec.ts is misleading because it makes it sound like clicking on the button will open the dialog, create the component, and save the project. In actuality, clicking the button will only open the dialog. It might be better to separate it into two tests. One tests opening the dialog and another tests when the dialog is closed, it creates the component and saves.