Unfortunately, the frontend is not fixed as of yet to allow WLAN creation without the PEF license. You can either:
(1) Obtain a temporary PEF license or
(2) Create the WLAN on the commandline:
You can try in CLI as below
config t
aaa authentication captive_protal cp_Prof)
aaa profile cp_aaa initial-role cp_prof)
wlan ssid-profile cp_ssid)
wlan virtual-ap cp_vap
ssid-profile cp_ssid
aaa_profile cp_prof)
Then you would assign the Virtual AP profile to the default ap-group:
config t
virtual-ap cp_vap