add pointer-events: none to host component so in case it is disabled,
the browser does not call click handlers registered to it.

add chai for better assertion messages

this way, the component can handle the click first and then the app handler
will have the correct component state in its click handler

With click handlers registered in the shadow dom, the qunit tests
can no longer simulate events correctly.
For these scenarios, the wdio tests will be used anyway.

- remove disabled check, CSS takes care of that