Could not use the specified VPC with multiple subnets under one AZ

[0dd]

Describe the bug
Could not use the specified VPC with multiple subnets under one AZ

To Reproduce
Use the VPC flag with one existing VPC with multiple subnets under a single AZ

Background Context

The ALB creation will need at least two subnets under two different AZs. By default, if there is only a single subnet under the AZ. The ALB creation will use that subnet for creation. Otherwise, the customer has to specify the subnet for ALB to serving to.

Cause
The class used to create a Fargate service along with ALB ApplicationLoadBalancedFargateService did not take the props for the taskSubnet but only the iVPC which did not specify the subnet to use for creating ALB. Then when passing the iVPC with multiple subnets under same AZ will lead to an error