Mark a few build-time-only third-party README.chromiums as NOT_SHIPPED

To avoid them being listed in about:credits

BUG=332521

Review-Url: https://codereview.chromium.org/1935233002
Cr-Commit-Position: refs/heads/master@{#391285}
GitOrigin-RevId: c11f4b9a2e07b096d77ad038d42b83d9203eb0bf
1 file changed