Unable to assign VLANs in non-scoped groups to interfaces

### NetBox version

v2.11.2

### Python version

3.7

### Steps to Reproduce

1. Create a new VLAN group named Group1, with no scope
2. Create a VLAN named VLAN1 in Group1
3. Attempt to assign this VLAN to a device or virtual machine interface

### Expected Behavior

The VLAN should appear in the list of available VLANs

### Observed Behavior

The VLAN is omitted from the list of available VLANs