Grant new auto-submit service account permissions

1. Permission to set CQ+2. The old auto-submit service accounts
   got this permission from being in the "Fuchsia Source Committers"
   group, but it seems wrong to have auto-submit be considered a
   committer, so I'm granting it direct permission instead.
2. Permission to remove Fuchsia-Auto-Submit+1 on behalf of humans.
   This won't be used yet, but I'm planning to teach auto-submit to
   remove the auto-submit label after exceeding the max CQ retries.

Bug: 417536657
Change-Id: Ie35bc6f4695d2da0acbb2a41df5261bad2ed97df
Reviewed-on: https://fuchsia-review.googlesource.com/c/Commit-Queue/+/1276804
Reviewed-by: Rob Mohr <mohrr@google.com>
2 files changed