[membrane_rtsp] Membrane.RTSP.describe/1 returns 401 when url has credentials

```elixir
iex> {:ok, session} = Membrane.RTSP.start_link("rtsp://admin:<PASSWORD>@<IP>:554/cam/realmonitor?channel=1&subtype=0")
iex> Membrane.RTSP.describe(session)
{:ok,
 %Membrane.RTSP.Response{
   status: 401,
   version: "1.0",
   headers: [{"CSeq", "1"}, {"Session", "2312949884"}],
   body: ""
 }}
``` 