Restrict access to release branch: release-R117 to LTS Refresher group.

BUG=b/430110587

Change-Id: I5ade7ae03b7fecd406b0d7c2f2827be750286f6f
Reviewed-on: https://cos-review.googlesource.com/c/All-Projects/+/106997
Reviewed-by: Chenglong Tang <chenglongtang@google.com>
Tested-by: He Gao <hegao@google.com>