Update background color of main switch track.

Bug: 175181773
Test: Run robotest and apply the widget in Settings and see the ui
Change-Id: Ie5bdb40a5cc1be17b6ebdb910dfbbaeb4042fb39

packages/SettingsLib/MainSwitchPreference/res/drawable/track_on_background.xml

@@ -20,7 +20,8 @@
     android:width="48dp"
     android:height="24dp"
     android:viewportWidth="48"
-    android:viewportHeight="24">
+    android:viewportHeight="24"
+    android:tint="@*android:color/switch_track_material">
 
   <group>
     <clip-path
@@ -28,7 +29,7 @@
 
     <path
         android:pathData="M0 0V24H48V0"
-        android:fillColor="@color/track_on" />
+        android:fillColor="@*android:color/white_disabled_material" />
   </group>
 
 </vector>

packages/SettingsLib/MainSwitchPreference/res/values-night/colors.xml

@@ -19,7 +19,6 @@
 
     <color name="title_text_color">@*android:color/primary_text_dark</color>
     <color name="thumb_off">#BFFFFFFF</color>
-    <color name="track_on">@*android:color/material_grey_600</color>
     <color name="track_off">@*android:color/material_grey_600</color>
 
 </resources>

packages/SettingsLib/MainSwitchPreference/res/values/colors.xml

@@ -19,7 +19,6 @@
 
     <color name="title_text_color">@*android:color/primary_text_light</color>
     <color name="thumb_off">#BFFFFFFF</color>
-    <color name="track_on">@*android:color/accent_device_default_dark</color>
     <color name="track_off">@*android:color/material_grey_600</color>
 
 </resources>