Automatic merge from submit-queue (batch tested with PRs 58104, 58492, 58491). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Optionally prevent metadata concealment firewall from being set

**What this PR does / why we need it**: GCP: allow a master to not include a metadata concealment firewall rule (if it's not running the metadata proxy).

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
GCP: allow a master to not include a metadata concealment firewall rule (if it's not running the metadata proxy).
```