Mark dehydrated devices in admin get devices endpoint (#18252)

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

docs/admin_api/user_admin_api.md

@@ -954,7 +954,8 @@ A response body like the following is returned:
       "last_seen_ip": "1.2.3.4",
       "last_seen_user_agent": "Mozilla/5.0 (X11; Linux x86_64; rv:103.0) Gecko/20100101 Firefox/103.0",
       "last_seen_ts": 1474491775024,
-      "user_id": "<user_id>"
+      "user_id": "<user_id>",
+      "dehydrated": false
     },
     {
       "device_id": "AUIECTSRND",
@@ -962,7 +963,8 @@ A response body like the following is returned:
       "last_seen_ip": "1.2.3.5",
       "last_seen_user_agent": "Mozilla/5.0 (X11; Linux x86_64; rv:103.0) Gecko/20100101 Firefox/103.0",
       "last_seen_ts": 1474491775025,
-      "user_id": "<user_id>"
+      "user_id": "<user_id>",
+      "dehydrated": false
     }
   ],
   "total": 2
@@ -992,6 +994,7 @@ The following fields are returned in the JSON response body:
   - `last_seen_ts` - The timestamp (in milliseconds since the unix epoch) when this
     devices was last seen. (May be a few minutes out of date, for efficiency reasons).
   - `user_id` - Owner of  device.
+  - `dehydrated` - Whether the device is a dehydrated device.
 
 - `total` - Total number of user's devices.