Fix appsearch filegroups to match package

The "java" directory in appsearch contains both a package structure and
subdirectories that include a package structure. Update the build
structure to match that.

This is part of a chunk of work necessary to avoidi unintentional
classes being included in the public documentation.

Bug: 187386774
Test: diff docs with/without package filter applied
Change-Id: I312d5cef014557b02d5c015899944ffdea8ca168

apex/appsearch/framework/Android.bp

@@ -23,12 +23,30 @@ package {
 
 filegroup {
     name: "framework-appsearch-sources",
+    srcs: [
+        ":framework-appsearch-internal-sources",
+        ":framework-appsearch-external-sources",
+    ],
+    visibility: ["//frameworks/base"],
+}
+
+filegroup {
+    name: "framework-appsearch-internal-sources",
     srcs: [
         "java/**/*.java",
         "java/**/*.aidl",
     ],
+    exclude_srcs: [":framework-appsearch-external-sources"],
     path: "java",
-    visibility: ["//frameworks/base"],
+}
+
+filegroup {
+    name: "framework-appsearch-external-sources",
+    srcs: [
+        "java/external/**/*.java",
+        "java/external/**/*.aidl",
+    ],
+    path: "java/external",
 }
 
 java_sdk_library {