Add device access to portal-test

[marbetschar]

It would be great to be able to test the org.freedesktop.portal.Device portal using the portal-test app. This seems not to be integrated right now - are there any plans to do so? Or did I miss something?

[orowith2os]

The Device portal is fairly bare as-is, so testing it doesn't really do anything off the top of my head. It would make sense to test once the OpenPipeWireRemote() methods are added, however.

We're still waiting on more WirePlumber and PipeWire changes to get all that going, afaik. @GeorgesStavracas would have more information on that, and reading the latest comment from @jadahl on the portal, a new method seems more appropriate (especially as, apparently, the Device portal isn't intended for application use?)