How to get a list of ports listening in a Fortigate firewall

The FortiGate doesn't care which protocol is running over the port 443, so you just need to create a policy and select the corresponding interfaces/addresses and as service you can select HTTPS. If it's a policy from internal network to WAN, be sure to select NAT also

It's look like that theinternal-switch-mode is set as switch¹ (by default). That means that all port on the internal interface are configured as they are only one:

Switch mode combines FortiGate unit interfaces into one switch with one address. Interface mode gives each internal interface its own address.²

so, as I understand, if in system global configuration you set: internal-switch-mode interface, you shall configure each port independently, so you will able to reconfigure port 1 and 2 then disable the other as @David say.

NB Before switching modes, all configuration settings for the interfaces affected by the switch must be set to defaults.²

Ref:

1. Fotigate "Interface" command CLI document
2. Fotigate "Global config" command CLI document