Fix ThemePicker build and exclude unused features

- Exclude Theme and Clock from builds since they are unused, should add
them back when the features are needed.

Screenshot: https://screenshot.googleplex.com/AeLSMUFq5EdndWr.png

Bug: 190354625
Test: m ThemePicker
Change-Id: I0219fa5b27354fc7afdcb5526e1b8e8e3d29b755
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 4f62429..bae1cb3 100755
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -48,6 +48,7 @@
         android:name="com.android.customization.picker.CustomizationPickerApplication"
         android:theme="@style/CustomizationTheme">
         <activity
+            tools:node="replace"
             android:name="com.android.wallpaper.picker.CustomizationPickerActivity"
             android:label="@string/app_name"
             android:resizeableActivity="false"
@@ -65,10 +66,6 @@
              </intent-filter>
         </activity-alias>
 
-        <activity android:name="com.android.customization.picker.theme.CustomThemeActivity"
-                  android:resizeableActivity="false"
-                  android:theme="@style/CustomizationTheme.NoActionBar"/>
-
         <activity android:name="com.android.customization.picker.ViewOnlyFullPreviewActivity"
             android:resizeableActivity="false"
             android:theme="@style/CustomizationTheme.NoActionBar"/>