Modifications to rate limiting settings. (#4091)

i18n/en.json

@@ -3043,6 +3043,10 @@
     "id": "model.config.is_valid.email_security.app_error",
     "translation": "Invalid connection security for email settings.  Must be '', 'TLS', or 'STARTTLS'"
   },
+  {
+    "id": "model.config.is_valid.max_burst.app_error",
+    "translation": "Max burst must be greater than zero."
+  },
   {
     "id": "model.config.is_valid.encrypt_sql.app_error",
     "translation": "Invalid at rest encrypt key for SQL settings.  Must be 32 chars or more."