Display the name of the creator for flags & skins (#3510)

## Description:

So artists get credit for the work they do.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

resources/lang/en.json

@@ -919,6 +919,9 @@
     "select_skin": "Select Skin",
     "selected": "selected"
   },
+  "cosmetics": {
+    "artist_label": "Artist:"
+  },
   "flag_input": {
     "title": "Select Flag",
     "button_title": "Pick a flag!",