[ssci] Add Shipped field to READMEs

This CL adds the Shipped field and updates the
License File field in Chromium READMEs within the
directory /net/third_party/nss.

See the LSC doc at go/lsc-chrome-metadata.

This CL was uploaded by git cl split.

R=davidben@chromium.org

Bug: b:285450740
Change-Id: I9fbaa982787c28560b3c3258a9fbc645f14cc7a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4659643
Reviewed-by: David Benjamin <davidben@chromium.org>
Commit-Queue: Anne Redulla <aredulla@google.com>
Cr-Commit-Position: refs/heads/main@{#1166971}
NOKEYCHECK=True
GitOrigin-RevId: 834cae1b8e73d0aef10973eaf48107f94b16786d