Add container to .aconfig

Change-Id: If809f6229cd69ba9fe8a78c8c598b6a5d8d2d334
Test: m
Bug: 328444881
diff --git a/services/accessibility/Android.bp b/services/accessibility/Android.bp
index 467adc7..7a99b60 100644
--- a/services/accessibility/Android.bp
+++ b/services/accessibility/Android.bp
@@ -58,6 +58,7 @@
 aconfig_declarations {
     name: "com_android_server_accessibility_flags",
     package: "com.android.server.accessibility",
+    container: "system",
     srcs: [
         "accessibility.aconfig",
     ],