There is no command for "no switchport"
That said, you CAN often set an IP directly on an interface in the ICX world in which case it becomes a Layer-3 interface just like on Cisco.
That said, typically we do not configure them that way. Instead we use VRIs (Virtual Router Interfaces), which Cisco refers to as SVIs (Software Virtual Interfaces)
If you type in CIDR notation such as /24, ICX will properly type your mask. Wish Cisco would do that, too.
This is from memory; I am not double-checking my work, but basically these are VRIs and SVIs respectively on the different platforms. Virtually identical meaning.
Vlan 123 name Test by port
untagged ethe 1/2/1
router-interface ve 123
interface ve 123
ip address 10.1.2.1/24
switchport mode access
switchport access vlan 123
ip address 10.1.2.1 255.255.255.0