Add missed plugin error translation (#9131)

i18n/en.json

@@ -3026,6 +3026,10 @@
     "id": "app.plugin.get_plugins.app_error",
     "translation": "Unable to get active plugins"
   },
+  {
+    "id": "app.plugin.get_statuses.app_error",
+    "translation": "Unable to get plugin statuses"
+  },
   {
     "id": "app.plugin.install.app_error",
     "translation": "Unable to install plugin."