enabled API coverage check for CBR service

Bug: 135956699
Test: Build
Change-Id: Iaa42b080c0e6a05c3cf7cc2e9febe70db4cb1338
diff --git a/Android.bp b/Android.bp
index 3f82eeb..68fd40b 100644
--- a/Android.bp
+++ b/Android.bp
@@ -16,6 +16,7 @@
         proguard_flags_files: ["proguard.flags"],
     },
     jarjar_rules: "cellbroadcast-jarjar-rules.txt",
+    plugins: ["java_api_finder"],
 }
 
 android_app {