Fixes WallpaperPickerGoogle Studio build

Fixes the resource issues introduced to Studio by ag/25842216 and ag/25839209

Fixes: 323334670
Flag: NONE
Test: Manually built and ran all AOSP and Google targets
Test: Manually ran instrumented and deviceless tests for all targets in
Studio and with atest

Change-Id: I4aa91e6a22f2eb825e770dcd4049ce312d66038d
diff --git a/Android.bp b/Android.bp
index 4b78713..8676f26 100644
--- a/Android.bp
+++ b/Android.bp
@@ -127,6 +127,7 @@
 //
 android_app {
     name: "ThemePicker",
+    package_name: "com.android.wallpaper",
     defaults: ["ThemePicker_defaults"],
 
     platform_apis: true,