Fix Kongregate F+

Attempts to reach were met with a Varnish error page presenting 54113.
Whether this error was due to Varnish or Fastly is unkown but irrelevant.

Change in User Agent necessary to avoid the Varnish error page.
Change in Accept necessary to avoid inifite 302 redirections.
Without BOTH of these changes, the attempt will fail.

With these changes, also able to switch to the simpler status_code method.

sherlock/resources/data.json

@@ -1163,8 +1163,11 @@
     "username_claimed": "blue"
   },
   "Kongregate": {
-    "errorMsg": "Sorry, no account with that name was found.",
-    "errorType": "message",
+    "errorType": "status_code",
+    "headers": {
+      "User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/116.0",
+      "Accept": "text/html"
+    },
     "regexCheck": "^[a-zA-Z][a-zA-Z0-9_-]*$",
     "url": "https://www.kongregate.com/accounts/{}",
     "urlMain": "https://www.kongregate.com/",