Fix County (maybe others) cards w/o footer items

[sentry-io]

Need to either pass an empty array as default, use one as the default param, or return an empty array if list is undefined. Or just don't call the function in the first place.

Sentry Issue: LANGUAGE-MAPPING-3W

TypeError: e.sort is not a function
  at utils (components/explore/utils.tsx:11:6)
  at c (components/explore/CustomCard.tsx:140:15)
...
(9 additional frame(s) were not displayed)