Theme the block listing shortcuts in the dashboard

Repurposing this. Shortcut module already provides a block, so we would just need a bit of theming.

This is a good exercise on how we want to handle this. E.g. we could do

.dashboard .block.block-shortcuts ul li {
    list-style: none;
}

But should that be in shortcut module css?
Should we alter the block from dashboard to add a dashboard/shortcuts library with css?
Should we just provide a consistent

.dashboard .block ul li {
    list-style: none;
}

and that's it?

FYI https://www.drupal.org/project/ideas/issues/3311180 ✨ [policy] Deprecate Shortcut module Needs work

FYI https://www.drupal.org/project/ideas/issues/3311180 ✨ [policy] Deprecate Shortcut module Needs work