feat: support attribute component names for focusable identification

[StephenRiosDev]

Feature Description

Support attribute component names, e.g. <custom-auro-button auro-button="true"></custom-auro-button> when detecting focusable elements.

Additional context

This is needed to support focusability detection when consumers are using custom tag names.

Exit criteria (To be determined by the Auro team)

Auro elements using custom tag names with tag-name attributes should be properly detected as focusable by the focusables utility.