Make user-trash icons look like trashcans

Summary: BUG: 399613

Test Plan:
{F7309835, size=full}

{F7309836, size=full}

Reviewers: #vdg, ngraham

Reviewed By: #vdg, ngraham

Subscribers: ngraham, kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D23685