[sddm-theme/lock screen] Improve appearance in software rendering mode (outlines and icons)
Summary: This patch improves the appearance of the sddm theme and the lock screen with software rendering in place (QT_QUICK_BACKEND=software) by adding an outline to the action buttons, correcting the error that prevented the username outline from appearing and by adding a background to the action buttons that are otherwise impossible to see on top of a very bright background in software rendering mode.
Before (white background):
After (white background):
Reviewed By: VDG, ngraham
Maniphest Tasks: T10325
Differential Revision: https://phabricator.kde.org/D19609