Allowlist gcloud to be run during the build

We obtain credentials for RBE through gcloud in case of builds on glapstations (i.e., glinux workstations at home). Hence gcloud needs to be able to run during the build for this credential fetching to work.
Related: https://b.corp.google.com/issues/320962825#comment11

Also, we no longer use prodcertstatus, so I've removed it from the allowlist.

Bug: b/320962825
Change-Id: I97ee7d53b2f490ba81ce94d13eaecb4e6a311914
Tested: ran a build on glinux workstation at home to confirm