check elb type in compare_subnets for elbv2 (#50203)

* Add check for elb type to fix difference between NLB and ALB AZ return structure

Fixes #49558

* Fix spacing for pep8 (hopefully) compliancE

* use empty array default instead of loadbalancer type detection

hat tip briantist

* spacing is probably important.

lib/ansible/module_utils/aws/elbv2.py

@@ -169,7 +169,7 @@ class ElasticLoadBalancerV2(object):
         # on the load balancer
         for subnet in self.elb['AvailabilityZones']:
             this_mapping = {'SubnetId': subnet['SubnetId']}
-            for address in subnet['LoadBalancerAddresses']:
+            for address in subnet.get('LoadBalancerAddresses', []):
                 if 'AllocationId' in address:
                     this_mapping['AllocationId'] = address['AllocationId']
                     break