Remove label-Bot-Commit permissions for group chromeos-bots.

All bots that use label-Bot-Commit are already in bot-commit-bots
which has label-Bot-Commit permissions inherited from
https://chromium.googlesource.com/All-Projects/+/refs/meta/config/project.config#30.


Bug: 408312604
Change-Id: I84870865820e43e9843076bc887f37418034e6bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/+/6454905
Reviewed-by: Joey Scarr <jsca@google.com>