[sddm-theme] Don't handle enter key when blurred
Summary:
Meaning pressing enter just wakes up the display.
Behaviour now matches lock screen.
BUG: 402957
Test Plan: Ran SDDM
Reviewers: Plasma, ngraham
Reviewed By: ngraham
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D17997