Set more aconfig_declarations containers to system in frameworks/base

Bug: 330354107
Test: CI

Flag: NONE

Ignore-AOSP-First: It is easier to detect all the mismatch in internal
master.

Change-Id: If6d417b269e23f205c21686d147e9249d47a18b9
diff --git a/services/backup/flags.aconfig b/services/backup/flags.aconfig
index 74adfe0..d53f949 100644
--- a/services/backup/flags.aconfig
+++ b/services/backup/flags.aconfig
@@ -1,4 +1,5 @@
 package: "com.android.server.backup"
+container: "system"
 
 flag {
     name: "enable_skipping_restore_launched_apps"
@@ -58,4 +59,4 @@
     description: "Increase BMM logging coverage in restore at install flow."
     bug: "331749778"
     is_fixed_read_only: true
-}
\ No newline at end of file
+}