Use the same avatar size in lock, login and logout screens
Currently the avatar in the logout screen is noticeably smaller than the avatar in the lock and logout screens.
This patch roughly bases the size value on what is produced in the lock and logout, and then applies it to the logout screen.
Before (logout screen):
After (logout screen):
Before (lock screen):
After (lock screen):
Reviewed By: VDG, ngraham
Subscribers: davidedmundson, ngraham, plasma-devel
Maniphest Tasks: T11093
Differential Revision: https://phabricator.kde.org/D25024