NethVoice: hide switchboard operator permission

[andrea-marchionni]

In the NethVoice administration interface, in the Configurations -> Profiles section, if there is at least one configured queue, the permission to activate the switchboard operator panel is also shown, which has not yet been implemented on this version.
It should be hidden

[edospadoni]

Test case

• Check the permission is now hidden

[edospadoni]

Testing release: https://github.com/nethesis/ns8-nethvoice/releases/tag/1.2.3-testing.2