Update theme for ChannelPanelActivity

- set correct switch style
- update background color

Fixes: 238845212
Test: visual
Change-Id: Iaf54fa5d98f7527543fc02d1108cbafe851bd574

res/drawable/button_border_selected.xml

@@ -15,10 +15,7 @@
   limitations under the License.
   -->
 <shape xmlns:android="http://schemas.android.com/apk/res/android"
-       xmlns:androidprv="http://schemas.android.com/apk/prv/res/android"
        android:shape="rectangle">
-    <solid
-        android:color="?androidprv:attr/materialColorSurfaceContainer" />
     <stroke
         android:width="2dp"
         android:color="?android:attr/colorAccent"/>

res/drawable/button_border_unselected.xml

@@ -18,7 +18,7 @@
        android:shape="rectangle">
     <stroke
         android:width="1dp"
-        android:color="@color/notification_importance_button_unselected"/>
+        android:color="?android:attr/colorAccent"/>
 
     <corners android:radius="@dimen/rect_button_radius" />
 </shape>