AWS::ElasticLoadBalancingV2::LoadBalancer - Issue with Drift Detection when we create AWS::ElasticLoadBalancingV2::LoadBalancer and AWS::ElasticLoadBalancingV2::TargetGroup.

## Instructions for CloudFormation Coverage New Issues Template

Quick Sample Summary:
1. Title -> AWS::ElasticLoadBalancingV2::LoadBalancer and AWS::ElasticLoadBalancingV2::TargetGroup. -Attribute-Existing Attribute
2. Scope of request ->
- AWS::ElasticLoadBalancingV2::LoadBalancer -> When we create a network load balancer and attach EIPS to it using 'SubnetMappings' property, the resource is being shown as drifted since the EIP is being taken as the subnet ID

- AWS::ElasticLoadBalancingV2::TargetGroup. -> The tags is supported by Target group resource but still CFN is showing false drift. Also, when we add just one attribute to the Target group using 'TargetGroupAttributes ' property, it is showing false drift as shown in screenshot attached below.

3. Expected behavior -> Actual values and expected values should be same.
4. Test case recommendation (optional) -> I have attaches the template that I have used for testing ->
[testDriftBehavior.txt](https://github.com/aws-cloudformation/aws-cloudformation-coverage-roadmap/files/4562586/testDriftBehavior.txt)

5. Links to existing API doc (optional) -> https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-elasticloadbalancingv2-targetgroup.html
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-elasticloadbalancingv2-loadbalancer.html

6. Category tag (optional) -> Compute
7. Any additional context (optional)