Cannot send REST request to /api/devices without applicationID

[zakini]

• [x] The issue is present in the latest release.
• [x] I have searched the issues of this repository and believe that this is not a duplicate.

What happened?

GET requests to /api/devices always result in a 500 response with the body:

{
  "error": "subject must be user",
  "code": 2,
  "message": "subject must be user",
  "details": []
}

What did you expect?

A 200 response with a list of devices

Steps to reproduce this issue

Steps:

1. Send a request to /api/devices with a grpc-metadata-authorization header with a valid API token (no query params, no request body)
2. Get a 500 response

Your Environment

Component	Version
Application Server	v3.16
Network Server	v3.14

---

This was raised in #530 in this comment and @brocaar asked for a separate ticket but as far as I can tell that didn't get created. As mentioned in that comment, specifying an applicationID fixes the issue, but the API docs don't mention this param being required.

[liangyuanpeng]

send REST request to /api/devices without applicationID

Work from my side. tested two version.

~ # ./lora-app-server version
3.4.0

~ # ./lora-app-server version
3.3.1