[sddm-theme/lock screen] Remove username shadow and show clock shadow only when unfocused
Summary: This patch removes the shadow from the usernames on the login and lock screens. It also restricts the clock shadow to just the opaque (unfocused) versions of each screen.
Test Plan:
Reviewers: VDG, ngraham, filipf
Reviewed By: VDG, ngraham, filipf
Subscribers: filipf, plasma-devel
Tags: Plasma
Maniphest Tasks: T10325
Differential Revision: https://phabricator.kde.org/D19468