Fix access to content: URLs with transient permissions
requested to merge vkrause/craft-blueprints-kde:work/android-backport-transient-permission-content-url-access-fix into master
Backport of https://codereview.qt-project.org/c/qt/qtbase/+/364893.
This fixes accessing content: URLs obtained via Intents rather than from the file dialog, or other sources where we don't get persistent permissions. This fixes for example to open files in Okular from the file manager or importing shared email attachments in Itinerary.