set exportable to true for aconfig.test.exported.flags

Test: m aconfig_test_java_library_exported
Bug: 310504781
Change-Id: Ib405febc739c49dff7340d43c65a7ec2b314d7de
diff --git a/tools/aconfig/aconfig/Android.bp b/tools/aconfig/aconfig/Android.bp
index 2c26166..00a6fee 100644
--- a/tools/aconfig/aconfig/Android.bp
+++ b/tools/aconfig/aconfig/Android.bp
@@ -47,6 +47,7 @@
 aconfig_declarations {
     name: "aconfig.test.exported.flags",
     package: "com.android.aconfig.test.exported",
+    exportable: true,
     container: "system",
     srcs: ["tests/test_exported.aconfig"],
 }