Fix Cloudron users API response shape ({users: [...]})

app/main.py

@@ -895,7 +895,10 @@ async def matrix_member_mxids(client: httpx.AsyncClient):
         f"{CLOUDRON_API}/api/v1/users",
         headers=cloudron_headers(),
     )
-    users = {u["email"].lower(): u["username"] for u in r.json()} if r.status_code == 200 else {}
+    users = (
+        {u["email"].lower(): u["username"] for u in r.json().get("users", [])}
+        if r.status_code == 200 else {}
+    )
     for email in await get_active_member_emails():
         username = users.get(email.lower())
         if username: