Description of problem:
admission webhook "datavolume-mutate.cdi.kubevirt.io" denied the request: quantities must match the regular expression '^([+-]?[0-9.]+)([eEinumkKMGTP][-+]?[0-9])$'

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

How reproducible:

Steps to Reproduce:
1. Navigating to Virtualization -> Catalog -> Instance types
2. click add volume
3. select use existing PVC radio option
4. select a PVC
5. select volume name
6. select instance type and preference
7. do not edit the size
8. try to save gets an error

Actual results:
volume creation failed

Expected results:
volume creation succeed

Additional info: