* simplify logic and fix some pattern-matching bugs
* add first pass at parsing combined expiry year and month from user input
* clean up code
* fix broken three-digit parsing case
* fix case where splitCombinedDateValues returns empty strings when the input is only a delimiter
* fix incorrect expectation of falsy negative integers
* clean up code
* split out logic from parseYearMonthExpiry
* move utils from vault to autofill