Initialize the small frame in KeyguardClockSwitch as invisible

The KeyguardClockSwitch starts with the small clock frame as visible,
which allows the clock to be seen in a bad state if it's bound before
switchToClock is called with the appropriate clock size.

Fixes: 247608708
Test: Manually checked large & small clock user switch
Change-Id: I0885d19e297ff5f881271ed0347e9699b3494928

packages/SystemUI/res-keyguard/layout/keyguard_clock_switch.xml

@@ -31,7 +31,8 @@
         android:layout_height="wrap_content"
         android:layout_alignParentStart="true"
         android:layout_alignParentTop="true"
-        android:paddingStart="@dimen/clock_padding_start" />
+        android:paddingStart="@dimen/clock_padding_start"
+        android:visibility="invisible" />
     <FrameLayout
         android:id="@+id/lockscreen_clock_view_large"
         android:layout_width="match_parent"