[MM-34076] Add Plugin API User custom status (#17435)

* add missing client for custom user status

* add custom user status plugin api

* update based on feedback review

* add GetCustomStatus

* update interfaces

i18n/en.json

@@ -1566,6 +1566,10 @@
     "id": "api.custom_status.recent_custom_statuses.delete.app_error",
     "translation": "Failed to delete the recent status. Please try adding the status first or contact your system administrator for details."
   },
+  {
+    "id": "api.custom_status.set_custom_statuses.update.app_error",
+    "translation": "Failed to update the custom status. Please add either emoji or custom text status or both."
+  },
   {
     "id": "api.email.send_warn_metric_ack.failure.app_error",
     "translation": "Failure to send admin acknowledgment email"