Embed an sdkinfo proto in the test media apex

This is used in sdkextensions_e2e_test to verify the sdk version gets
bumped correctly for multiple updated modules.

Bug: 149815613
Test: sdkextensions_e2e_test
Change-Id: If98002f378c82d7d1d1454b40b285c3a4f3ed959
diff --git a/apex/testing/Android.bp b/apex/testing/Android.bp
index 376d3e4..a04ab3f 100644
--- a/apex/testing/Android.bp
+++ b/apex/testing/Android.bp
@@ -17,6 +17,7 @@
     manifest: "test_manifest.json",
     file_contexts: ":com.android.media-file_contexts",
     defaults: ["com.android.media-defaults"],
+    prebuilts: ["sdkinfo_45"],
     installable: false,
 }