support scss as well as css about cypress-lit

[simonireilly]

@ShellyDCMS

I would need more information on what you are trying to achieve in order to help.

In general, this library is not part of your bundling/transpiling tool chain, it should only interact with the output.

[ShellyDCMS]

@simonireilly
When I follow this example with a lit component using css, it works fine.
When I try it for a component with scss, I get this error in cypress:
(uncaught exception) TypeError: Failed to set the 'adoptedStyleSheets' property on 'ShadowRoot': Failed to convert value to 'CSSStyleSheet'.

I failed to find a working example of lit component with scss and cypress component testing.
Would appreciate any pointers.