Add flag for reading from new storage

Bug: 312235596
Test: m
(cherry picked from https://android-review.googlesource.com/q/commit:62fc0df590cb1b3cd9245d09a5a9562b54d96ab1)
Merged-In: I41f565dd2149d7b0cfeea97f083a5a8aee922886
Change-Id: I41f565dd2149d7b0cfeea97f083a5a8aee922886

NOTE FOR REVIEWERS - original patch and result patch are not identical.
PLEASE REVIEW CAREFULLY.
Diffs between the patches:
     name: "use_new_storage_value"
> +    namespace: "core_experiments_team_internal"
> +    description: "When enabled, read the new storage value in aconfig codegen, and actually use it."
> +    bug: "312235596"
> +}
> +
> +flag {

Original patch:
 From 62fc0df590cb1b3cd9245d09a5a9562b54d96ab1 Mon Sep 17 00:00:00 2001
From: Ted Bauer <tedbauer@google.com>
Date: Tue, 06 Aug 2024 13:15:24 +0000
Subject: [PATCH] Add flag for reading from new storage

Bug: 312235596
Change-Id: I41f565dd2149d7b0cfeea97f083a5a8aee922886
Test: m
Flag: EXEMPT test only

Change-Id: I942cb9a7d9c27837bd3ba9e061884217ae72be30