Automatic merge from submit-queue (batch tested with PRs 56600, 56814). 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>.

Fix volume size allocation in gcd_pd

**What this PR does / why we need it**:
GCE PDs are allocated in chunks of GBs not GiB but CreateVolume function incorrectly creates volume in chunks of GiB.  
1 GiB = 1024 * 1024 * 1024 Bytes
1 GB = 1000 * 1000 * 1000 Bytes

**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 #56081

**Special notes for your reviewer**:

**Release note**:

```release-note
Fixed dynamic provisioning of GCE PDs to round to the next GB instead of GiB
```