Build mobly-bundled-snippets as APK instead of android_library

Bug: 254088877
Test: m mobly-bundled-snippets
Change-Id: If15f5d9b6b9341233fe352e9160c93eb628bf300
diff --git a/Android.bp b/Android.bp
index 8dc752f..ad7cbe8 100644
--- a/Android.bp
+++ b/Android.bp
@@ -16,7 +16,7 @@
     default_applicable_licenses: ["Android-Apache-2.0"],
 }
 
-android_library {
+android_app {
     name: "mobly-bundled-snippets",
     static_libs: [
         "androidx.test.runner",