Collection list: If no collection image, fall back to first-available product image

[bredowmax]

Describe the enhancement you'd like
In Dawn 1.0.0, Collection List appears incomplete if a collection doesn't have an image added. Other themes fall back to the best-available alternative: the first image of the first product in the collection. I'd like this enhancement for Dawn

Additional context/screenshots

[martinamarien]

Thanks for creating this issue @bredowmax.
Should be fixed on main now.