Fix `image-alt` violations

[DanielCliftonGuardian]

WCAG: 2.0 A (1.1.1)
Affected: 8 stories
Fix: Add alt attribute to images, or role="presentation" for decorative images

Affected Components
Components/InteractiveLayoutAtom (1 story)
Components/SlotBodyEnd/BrazeEpics (7 stories)

[petternitter]

Moving this to backlog, see comment in parent ticket #15058