Kirigami.Icon: Fix loading bigger images when source is a URL
Summary:
Port to using the QImage::load() that takes a QIODevice and only do it when the
execution is finished, instead of upon readyRead(). This makes sure that we are
only processing the icon when is fully downloaded.
BUG: 407409
BUG: 400312
Test Plan: Reproduced the bug and fixed it
Reviewers: Frameworks, Kirigami, mart
Reviewed By: Kirigami, mart
Subscribers: broulik, plasma-devel
Tags: Kirigami
Differential Revision: https://phabricator.kde.org/D22952