Fix storage class not being selected properly

[momesgin]

Summary

Fixes #10765

The current logic pre-selects the storage class if a default storage class exists(i.e. it has annotations: {'storageclass.kubernetes.io/is-default-class': 'true'}) and no storage class is already set. Two scenarios needed to be addressed:

1. You've saved a storage class different from the default one and are currently viewing it
2. During editing, you've selected a storage class and switched tabs

Areas or cases that should be tested

In the summary^.

Areas which could experience regressions

n/a

Screenshot/Video

10765.mov

Checklist

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[rak-phillip]

LGTM