Fix issues with 'disappearing' WL ifaces (when not assigned as part of any LAN bridges)
* related to assignments of VLANs, LAN bridges and WL interfaces on Advanced/VLAN (advanced-vlan.asp)
* any existing WL interfaces not assigned as part of any LAN bridges would simply 'disappear' from any/all web admin/UI pages (after saving settings on advanced-vlan.asp and rebooting)
* try to ensure any/all previously configured WL interfaces are still properly detected, even when not a member/part of a LAN bridge (therefore, available to be selected and/or re-assigned via the web UI)