Add optional for now so we can deploy

[nlitwin]

No description provided.

[vikasrohit]

@nlitwin do you know why this error appeared? Did we removed tc-btn from appirio-styles? And if we include @import 'topcoder/tc-buttons';, we can get rid of this error without making it optional.

[nlitwin]

I think the error is that there is no standalone .tc-btn class anymore. It was changed awhile ago to be button.tc-btn. I think that is the error, but I'm not sure why it's showing up now after all this time.

[nlitwin]

I think I fixed the error as well as fix the intro js CSS that has been broken for half a year lol

[vikasrohit]

I thought of the same reason, but it is not due the missing standalone class, rather it is due to missing import of tc-buttons.