Username / password not retained in Eth RPC URL

[ulope]

Describe the bug

In the configuration response the Raiden node delivers to the webui the Eth RPC URL is passed in the web3 field.
It seems the auth part (e.g. https://<user>:<password>@someurl.ext) is not retained when constructing the Eth node URL.

Steps to reproduce

Steps to reproduce the behavior:

1. Configure Raiden to use an Eth node URL with authentication (e.g. infura with the "project secret required" setting enabled)
2. Open the webui
3. Notice an JSON RPC connection error!
4. The request does not contain an auth header

Expected behavior

The auth information to be retained

System:

• OS: [e.g. iOS]
• Browser Safari 14.01
• Raiden 1.1.1.dev325+g4050ab976
• WebUI 1.0.2