Allow AppSearch's icing library access to libutf.

Bug: 169826971
Test: Builds, AppSearch presubmit
Change-Id: I294c3d0bb6df7614f9f281db6462f7af572746c0
diff --git a/Android.bp b/Android.bp
index e0288bf..837c0fe 100644
--- a/Android.bp
+++ b/Android.bp
@@ -70,6 +70,7 @@
 
     apex_available: [
         "//apex_available:platform",
+        "com.android.appsearch",
         "com.android.extservices",
     ],
 }