php8.0: Compatibility fixes

api/controllers/Circuits.php

api/controllers/Common.php

api/controllers/Tools.php

api/controllers/User.php

api/controllers/Vlans.php

api/controllers/Vrfs.php

app/admin/2fa/index.php

app/admin/2fa/save.php

app/admin/api/index.php

app/admin/circuits/edit-circuit-submit.php

app/admin/circuits/edit-logical-circuit-submit.php

app/admin/circuits/edit-options-submit.php

app/admin/circuits/edit-provider-submit.php

app/admin/customers/edit-submit.php

app/admin/devices/edit-result.php

app/admin/devices/edit-snmp.php

app/admin/firewall-zones/mapping.php

app/admin/firewall-zones/zones-edit-result.php

app/admin/groups/ad-search-group-result.php

app/admin/groups/edit-group-result.php