Automatic merge from submit-queue. 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>.

Fixes the regression of GCEPD not provisioning correctly on GKE alpha clusters.

Fixes the regression by better distinguishing between single-zone and multi-zone PDs.

**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 #59047

**Special notes for your reviewer**: All PD and dynamic provisioning e2e tests pass, manually verified provision, delete, attach, and detach of both single-zone and multi-zone PDs. Will create e2e tests for multizone PDs in a separate PR.

**Release note**:


/sig storage
/assign @saad-ali