Pull Request

🤨 Rationale

Fixes #2163

prominent appearance now gives the current/last breadcrumb item an accent color (rather than all but the last)
breadcrumb item now uses same focus styling as anchor, i.e. double underline and accent color (rather than a double outline)
breadcrumb item with missing/empty href is now the same color as a disabled link (rather than body font color)
breadcrumb item now, like the anchor, remains underlined when clicking it (rather than the underline disappearing)
spacing between breadcrumb item text and separators ('/') increased from 4px to 8px
I did not want to include both hover and hoverActive in the breadcrumb interactions story, so I changed createMatrixInteractionsFromStates to handle empty arrays for any of the states.

Added visual tests for no-href states, as well as interaction states.

[x] I have updated the project documentation to reflect my changes or determined no changes are needed.