XDG desktop portal utils implicitly rely on few portal interfaces.
This change makes those interfaces explicit.
Bug: chromium:1291247
Change-Id: I3c300f33d04bfa8857ac9f1f9d634dbfc077e591
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/258720
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Commit-Queue: Salman Malik <salmanmalik@google.com>
Cr-Commit-Position: refs/heads/main@{#36557}
