Update defaultMessages.json to include captcha defaultMessage

app/soapbox/locales/defaultMessages.json

@@ -905,6 +905,15 @@
     ],
     "path": "app/soapbox/features/audio/index.json"
   },
+  {
+    "descriptors": [
+      {
+        "defaultMessage": "Click the image to get a new captcha",
+        "id": "registration.captcha.hint"
+      }
+    ],
+    "path": "app/soapbox/features/auth_login/components/captcha.json"
+  },
   {
     "descriptors": [
       {