Set preference background color as transparent

- IllustrationPreference
- MainSwitchPreference

Bug: 280554568
Test: Visual
Change-Id: I5e49b39b4896e29dfc684a27c3ff44f606c256b2
diff --git a/packages/SettingsLib/IllustrationPreference/res/layout/illustration_preference.xml b/packages/SettingsLib/IllustrationPreference/res/layout/illustration_preference.xml
index eecb4bf..685e259 100644
--- a/packages/SettingsLib/IllustrationPreference/res/layout/illustration_preference.xml
+++ b/packages/SettingsLib/IllustrationPreference/res/layout/illustration_preference.xml
@@ -19,7 +19,6 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_height="wrap_content"
     android:layout_width="match_parent"
-    android:background="?android:attr/colorBackground"
     android:importantForAccessibility="noHideDescendants"
     android:gravity="center"
     android:orientation="horizontal">
diff --git a/packages/SettingsLib/MainSwitchPreference/res/layout-v33/settingslib_main_switch_bar.xml b/packages/SettingsLib/MainSwitchPreference/res/layout-v33/settingslib_main_switch_bar.xml
index 2c2ad92..eb877b5 100644
--- a/packages/SettingsLib/MainSwitchPreference/res/layout-v33/settingslib_main_switch_bar.xml
+++ b/packages/SettingsLib/MainSwitchPreference/res/layout-v33/settingslib_main_switch_bar.xml
@@ -19,7 +19,6 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_height="wrap_content"
     android:layout_width="match_parent"
-    android:background="?android:attr/colorBackground"
     android:minHeight="?android:attr/listPreferredItemHeight"
     android:paddingEnd="?android:attr/listPreferredItemPaddingEnd"
     android:paddingStart="?android:attr/listPreferredItemPaddingStart"