Move libicing.so out of /usr/lib, into the appsearch apex.

Bug: 169826971
Test: Presubmit
Change-Id: Ibe5dd5014c5a70cb5b0fcf3eb33db9911047bdc8

apex/appsearch/Android.bp

@@ -29,6 +29,7 @@ apex {
     key: "com.android.appsearch.key",
     certificate: ":com.android.appsearch.certificate",
     updatable: false,
+    jni_libs: ["libicing"],
     generate_hashtree: false,
 }
 

apex/appsearch/service/Android.bp

@@ -53,9 +53,6 @@ java_library {
         "framework-appsearch.impl",
         "unsupportedappusage", // TODO(b/181887768) should be removed
     ],
-    required: [
-        "libicing",
-    ],
     defaults: ["framework-system-server-module-defaults"],
     permitted_packages: [
         "com.android.server.appsearch",