Delete user containing `+` in username returns 404 but user gets deleted

## Steps to reproduce
1. Create a new user containing +: `user+plus`
2. Try to delete the created user - `404` ❗
```bash
curl -XDELETE "https://localhost:9200/graph/v1.0/users/user+plus' -u admin:admin -vk
```
```yaml
< HTTP/1.1 404 Not Found

{
"error": {
"code": "itemNotFound",
"innererror": {"date":"2025-02-18T11:58:19Z","request-id":"..."},
"message": ""
}
}
```
3. List user - user gets deleted ❗
```bash
curl 'https://localhost:9200/graph/v1.0/users' -uadmin:admin -vk | jq
```

## Expected behavior
204

## Actual behavior
404 Not Found
but user gets deleted