Allow to have wider password dialog while preffering minimum size

BUG:380399

kded/passworddialog.ui

@@ -11,14 +11,14 @@
    </rect>
   </property>
   <property name="sizePolicy">
-   <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+   <sizepolicy hsizetype="MinimumExpanding" vsizetype="MinimumExpanding">
     <horstretch>0</horstretch>
     <verstretch>0</verstretch>
    </sizepolicy>
   </property>
   <property name="maximumSize">
    <size>
-    <width>480</width>
+    <width>640</width>
     <height>16777215</height>
    </size>
   </property>