UI: Import VM unable to match the VLAN 0 to Untagged VLAN

### problem

While importing VM from vcenter with CloudStack UI, VMs on vCenter with VLAN 0 are expected to be allowed to import to 'Untagged' VLAN guest networks in CloudStack. But it doesn't allow.

### versions

4.22.0.0

### The steps to reproduce the bug

1.Import a VM in vCenter with NIC on network without VLAN i.e VLAN 0.
2. Try selecting the guest network (shared for example) with 'Untagged' VLAN.

...

### What to do about it?

UI needs to be fixed.

Reproduce the import flow described in the issue: import a vCenter VM whose NIC uses VLAN 0, then select a shared guest network with an Untagged VLAN. Trace the UI's guest-network matching and identify where VLAN 0 is rejected; done means the network can be selected successfully and the existing import flow still works.

Written by the indexing model from the issue text.