gnomescreencast: Embed monitor connector as stream property
requested to merge salmanmlk/xdg-desktop-portal-gnome:add_monitor_connector_to_stream_property into main
If a screencast session is screencasting from multiple monitors, it is not possible to distinguish which stream (or PipeWire stream node id) belongs to which connected monitor (such information may be useful to the caller when if they want to embed the stream in a window that and name it after the monitor connector, for example). This change adds optional metadata for monitor streams to also return the monitor connector name with the stream.
Ideally, this metadata should equip the caller to get more information about display from the following Wayland interfaces:
- https://wayland.freedesktop.org/docs/html/apa.html#protocol-spec-wl_output
- https://wayland.app/protocols/xdg-output-unstable-v1
Related: https://github.com/flatpak/xdg-desktop-portal/pull/832