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>.

Add bound/unbound pv/pvc volume metrics

**What this PR does / why we need it**:

Fix two bugs in bound/unbound pv/pvc volumes metric e2e test:

1. Check `HasRegisteredMaster` in `BeforeEach` instead of each tests because we will grab the metrics in `BeforeEach`

2. Fix `calculateRelativeValues` bug, if there are other PV/PVC exist in the cluster, `calculateRelativeValues` will return a map like `map[string]int64{"some-storage-class-name": 0}`, this will lead to test failure. We should skip these unchanged numbers.

**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 #59517

**Release note**:

```release-note
NONE
```

/sig storage