Automatic merge from submit-queue (batch tested with PRs 63386, 64624, 62297, 64847). 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>.

Refactoring GCE Disk APIs to use generated client

**What this PR does / why we need it**: Improves maintainability and testing of GCE disks code.

**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 #62296

Note that `gen.go` and `gen_test.go` are generated files.

I'm planning to do a more extensive refactor that takes advantage of the generated cloud provider mocks, but that'll be in a separate PR and will be a larger change.

/cc @davidz627
/assign @saad-ali 
/release-note-none
/sig storage