QML applets need to manage padding by themselves
Summary:
remove our padding from qml kcms
this fixes the cutted away shadow for InlineMessage
Test Plan: InlineMessages work better now
Reviewers: Plasma, hein
Reviewed By: Plasma, hein
Subscribers: hein, abetts, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D12515