Fix dry run intg test with right upgrade policy default (#8582)

Author: NicholasBlaskey

integration/tests/dry_run/dry_run_test.go

@@ -148,7 +148,8 @@ managedNodeGroups:
 
 privateCluster:
   enabled: false
-upgradePolicy: {}
+upgradePolicy:
+  supportType: ""
 vpc:
   autoAllocateIPv6: false
   cidr: 192.168.0.0/16