Add vpc-id to leaked eni filters

[jchen6585]

What type of PR is this?

improvement

Which issue does this PR fix?:

N/A

What does this PR do / Why do we need it?:
Adds a VPC-ID filter when checking for leaked ENIs for better filtering.

Testing done on this change:

Verified that (for testing purposes changed the loop to check every minute rather than hour during testing: https://github.com/aws/amazon-vpc-cni-k8s/blob/master/pkg/awsutils/awsutils.go#L390)

• CNI tagged ENIs are cleaned up properly after manually adding them through EC2 console.
  • Tagged with node.k8s.amazonaws.com/createdAt: <time_stamp>
  • Tagged with node.k8s.amazonaws.com/instance_id: <instance_id>
  • Tagged with cluster.k8s.amazonaws.com/name: <cluster_name>
  • Description starts with aws-K8S-
• Untagged ENIs are not cleaned up.
• CNI tagged ENIs on a different VPC are not cleaned up.
• Verified VPC ID is populated in the DescribeNetworkInterface call
  • Request:{method:DescribeUserInterfaces, request-id:<request-id>, request:{\"InterfaceIds\":null, \"SubnetIds\":null, \"SecurityGroupIds\":null, \"PrivateAddresses\":null, \"InstanceIds\":null, \"PrivateDnsNames\":null, \"InstancePrivateDnsNames\":null, \"MacAddresses\":null, \"VpcId\":\"<vpc-id>\", [...]

Will this PR introduce any new dependencies?:

N/A

Will this break upgrades or downgrades? Has updating a running cluster been tested?:
N/A

Does this change require updates to the CNI daemonset config files to work?:

N/A

Does this PR introduce any user-facing change?:

N/A

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jayanthvn]

lgtm