Add tests for bulk of InteractivePaycardComponent

[brendoncaulkins]

This will raise your global coverage to 80%+ for all four major categories, which does a good deal of progress towards resolving #4 .

Adding tests for the CardComponent is still up for grabs.

Once this is through, I would suggest adding a coverage enforcement mechanism, like https://www.npmjs.com/package/karma-threshold-reporter to keep your coverage in check against future code changes..

Happy Hacktoberfest !!

[milantenk]

Thank you for the suggestion regarding the code coverage threshold value! 😄 I created an issue for that, I'll do it as I'll have some time for it.