UI: Unable to select edge zone during iso registration

[kiranchavala]

problem

UI: Unable to select edge zone during iso registration

versions

ACS : 4.20.0

Hypervisor : KVM

The steps to reproduce the bug

1. Create a edge zone
2. Navigate to Images> ISO > Select direct download
3. In the zone drop, the edge zone doesn't show up

#8142

What to do about it?

End user should be able to select the edge zone during iso registration