Make avatar icon dpr aware aka HiDPI rendered
Test Plan: Locally tested under Wayland : couldn't make a screenshot because of https://bugs.kde.org/show_bug.cgi?id=409762
Reviewers: Plasma, ngraham
Reviewed By: ngraham
Subscribers: crossi, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D25395