File picker not using portal

[thatLeaflet]

When choosing an ISO to launch, the snap Boxes seems to not use portals to launch the file picker. This results in an older style of the file picker being used and I can't select my ISO because it's stored on a separate drive that the snap Boxes does not have permission to access.

Screenshot of snap file picker: notice the old style and that my removable drive is not present in left bar:

The flatpak Boxes does not have either of these issues.

Screenshot of flatpak file picker: notice the newer style and that my removable drive is present in left bar:

[soumyaDghosh]

https://github.com/ubuntu/gnome-boxes/blob/stable/snap/snapcraft.yaml#L76

The portals is disabled. Not sure why!