floating-label: explore/implement markup restructuring for autofill reactivity

[ArtBlue]

In some browsers, autofill tends to conflict with the floating label. For this issue, explore ways to restructure the markup and use :autofill selector to handle these conflicting use cases:

Note

Some background from Ian regarding a fix on the ebay ui side...

There is a known issue with chrome and autofill. To get around it we have to check for the change in background color:

https://stackoverflow.com/questions/35049555/chrome-autofill-autocomplete-no-value-for-password/35783761#35783761

Its possible Chrome may have added a new colour, in which case we need to update our code here:

https://github.com/makeup/makeup-js/blob/master/packages/makeup-floating-label/index.js#LL61C1-L61C1

Floating label code is referenced here in coreUI:
https://github.com/eBay/ebayui-core/blob/master/src/components/ebay-textbox/component-browser.js#L36