Description of problem:
when trying to attach a new disk (from wizard or disks tab),
the StorageClass dropdown shows every StorageClass as default if the annotation 'storageclass.kubernetes.io/is-default-class' exists on the SC instead of checking the value of the annotation to be 'storageclass.kubernetes.io/is-default-class = "true"'

Version-Release number of selected component (if applicable):
4.11

How reproducible:
100%

Steps to Reproduce:
1. go to Catalog -> select any template -> Customize VirtualMachine -> Review...
2. move to disks tab and click add disk wait for StoageClass dropdown to load
3. the selected option in the dropdown will be the first SC in the list with the annotation exists on yaml
4. open dropdown and see all SC with the annotation marked as (default) in option description

Actual results:
dropdown is selected with SC that has 'storageclass.kubernetes.io/is-default-class' annotation exists

Expected results:
dropdown is selected with SC that has 'storageclass.kubernetes.io/is-default-class = "true"'

Additional info: