fix: 8tracks

Use username availability endpoint from regflow with predictable
response language (en-us).

Referenced by #2318
Fixes #2332
Closes #2333 (removes target rather than fixes)

sherlock_project/resources/data.json

@@ -31,9 +31,13 @@
     "username_claimed": "blue"
   },
   "8tracks": {
-    "errorMsg": "This page has vanished",
     "errorType": "message",
+    "errorMsg": "\"available\":true",
+    "headers": {
+      "Accept-Language": "en-US,en;q=0.5"
+    },
     "url": "https://8tracks.com/{}",
+    "urlProbe": "https://8tracks.com/users/check_username?login={}&format=jsonh",
     "urlMain": "https://8tracks.com/",
     "username_claimed": "blue"
   },