Unable to connect to graphic server when using a proxy with params in the URI

This is a forwarded issue from:

https://gitlab.com/virt-viewer/virt-viewer/-/issues/24

TL;DR is that spice-gtk doesn't appear to cope with a proxy URI containing URI parameters like proxy=http://10.19.10.40:29876?token=m0944xfj3logi184kfb3

It thinks the params are part of the port

(remote-viewer.exe:3052): GSpice-WARNING \*\*: 09:49:02.056: Invalid uri port: 29877?token=r5x2wroym7fd5zadbari

and indeed looking at spice_uri_parse I can see it doesn't try to parse params.