Keep state query parameters when redirecting to "main" application

The following code adds the jwt to the referrer value (ie the "main" application url):
https://github.com/dwyl/auth/blob/9744fe50c697b613749f07c55b10bcb19744e83d/lib/auth_web/controllers/auth_controller.ex#L384-L385

However it will remove all existing query parameters and replace them with only the jwt:

```elixir
jwt = "fake_jwt"
state = "http://localhost:4000/admin?name=bob"
List.first(String.split(URI.decode(state), "?")) <> "?jwt=" <> jwt
# returns http://localhost:4000/admin?jwt=fake_jwt
```

Would it be better to concatenate the jwt to the exsting query parameter or is it intentional to only keep jwt