Add apex structure to appsearch module.

This change adds file_contexts for appsearch.

Bug: 144874026
Test: manual
Change-Id: Id8cba2eab3dbaab252eb42095e2ed265446b93c8
diff --git a/apex/com.android.appsearch-file_contexts b/apex/com.android.appsearch-file_contexts
new file mode 100644
index 0000000..9398505
--- /dev/null
+++ b/apex/com.android.appsearch-file_contexts
@@ -0,0 +1 @@
+(/.*)?           u:object_r:system_file:s0