Count of VLANs is incorrect when displaying vlan_groups

[jifox]

Environment

• Python version:
• Nautobot version: 4aa3f3706287 (v1.0.1)

Steps to Reproduce

1. Add non concurrent VLANs to a vlan Group
2. display the vlan group

Expected Behavior

The "VLANs" count should match the vlans in this group

Observed Behavior

The count ist higher that the ammount of vlans defined in Nautobot

I argue that the lines showing "VLANs avaliable" will be counted as VLANs too

[scetron]

@glennmatthews if this is done with review, I can take it

[glennmatthews]

Thanks!