NAT-315: Restore ISIS should be optional in migrate iptrunk

gso/workflows/iptrunk/migrate_iptrunk.py

@@ -559,8 +559,6 @@ def update_netbox(
     target=Target.MODIFY,
 )
 def migrate_iptrunk() -> StepList:
-    should_restore_isis_metric = conditional(lambda state: state["restore_isis_metric"])
-
     """Migrate an IP trunk.
 
     * Reserve new interfaces in Netbox