[ECS] [fargate]: service failed to register targets in target-group in a different VPC

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**Tell us about your request**
Allow Fargate tasks to be registered to a Target group in a different VPC

**Which service(s) is this request for?**
Fargate, ECS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
While trying to register a ECS/fargate task to a target group in a different VPC, I get the following error:

`service test failed to register targets in target-group test with (error The Availability Zone for IP address 'x.x.x.x' must be 'all' for Application Load Balancer target groups, when not within the VPC)`

I can manually register the task using aws CLI using:
`aws elbv2 register-targets --target-group-arn --targets Id=x.x.x.x,AvailabilityZone=all`

**Are you currently working around this issue?**
No

Start by reviewing the reported Fargate and ECS behavior and the AWS CLI register-targets workaround described in the issue. Confirm the cross-VPC target-group scenario and the required AvailabilityZone value; done means the service can register the task without requiring manual CLI registration.

Written by the indexing model from the issue text.