[plugin/aws] Refactor AwsEc2SecurityGroup pre_delete_resource

[lloesche]

Motivation

In the past the resource didn't have group_ip_permissions and group_ip_permissions_egress so the pre_delete method fetched them. Now that they are being collected and part of the node that extra fetch during deletion is no longer necessary.

Desired Behavior

Use the data already present in the node, instead of fetching it again.

Additional Context

No response