Improve SDDS hero XB integration

Line styling is on case study so crossing that one off.

Alan *may* do this as part of:

https://git.drupalcode.org/project/demo_design_system/-/merge_requests/53

kristen pol → credited alan.cole → .

Alan added #3.

Update summary.

Added another item.

Last item was done via:

📌 Tweaks to SDDS subtheme components for XB demo Fixed

only item left here is being able to set the background image.

The background isn't a priority right now so moving to postponed.