[sddm-theme/lock screen] Adjust login and lock screen blur effect

Summary: This patch modifies the login screen and lock screen blur effect.

Test Plan:
Before:
{F6643726}
After:
{F6643728}

Any and all input is appreciated!

Reviewers: #vdg, ngraham, #plasma, davidedmundson, filipf

Reviewed By: #vdg, ngraham

Subscribers: plasma-devel

Tags: #plasma

Maniphest Tasks: T10325

Differential Revision: https://phabricator.kde.org/D19409

lookandfeel/contents/components/WallpaperFader.qml

@@ -49,7 +49,7 @@ Item {
     FastBlur {
         id: wallpaperBlur
         anchors.fill: parent
-        radius: 100 * wallpaperFader.factor
+        radius: 50 * wallpaperFader.factor
     }
     ShaderEffect {
         id: wallpaperShader
@@ -62,9 +62,9 @@ Item {
             textureMirroring: ShaderEffectSource.NoMirroring
         }
 
-        readonly property real contrast: 0.45 * wallpaperFader.factor + (1 - wallpaperFader.factor)
-        readonly property real saturation: 1.7 * wallpaperFader.factor + (1 - wallpaperFader.factor)
-        readonly property real intensity: (wallpaperFader.lightBackground ? 1.7 : 0.45) * wallpaperFader.factor + (1 - wallpaperFader.factor)
+        readonly property real contrast: 0.65 * wallpaperFader.factor + (1 - wallpaperFader.factor)
+        readonly property real saturation: 1.6 * wallpaperFader.factor + (1 - wallpaperFader.factor)
+        readonly property real intensity: (wallpaperFader.lightBackground ? 1.7 : 0.6) * wallpaperFader.factor + (1 - wallpaperFader.factor)
 
         readonly property real transl: (1.0 - contrast) / 2.0;
         readonly property real rval: (1.0 - saturation) * 0.2126;