AWS::CodeDeploy::BlueGreen !Ref in AWS::ECS::TaskDefinition-ContainerDefinition-Image does not trigger CodeDeploy deployment

## 1. Title
#### AWS::ECS::TaskDefinition-ContainerDefinition-Image

## 2. Scope of request
Current issue we are experiencing: When updating the Image property of the TaskDefinition (for example choosing different tag) using AWS::CodeDeploy::BlueGreen and the Image property contains the intrinsic Ref function, no CodeDeploy deployment is triggered.
When replacing the intrinsic Ref function with the expected hard coded value the CodeDeploy deployment is triggered as expected when the Image property is updated.

## 3. Expected behavior

#### Intrinsic Ref functions inside the Image property should work together with AWS::CodeDeploy::BlueGreen

## 4. Suggest specific test cases

#### Common use case: Using Ref for account and region specific details
``` JSON
"Image": {
"Fn::Join": [
"",
[
{
"Ref": "AWS::AccountId"
},
".dkr.ecr.",
{
"Ref": "AWS::Region"
},
".",
{
"Ref": "AWS::URLSuffix"
},
"/:"
]
]
}
```

## 5. Helpful Links to speed up research and evaluation

[ECS Blue/Green docs](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/blue-green.html)

## 6. Category

Use the categories as displayed in the AWS Management Console (simplified):

1. Compute (ECS)
2. Developer Tools (CodeDeploy)

Start with the linked ECS Blue/Green documentation and reproduce the issue using an AWS::ECS::TaskDefinition-ContainerDefinition-Image value built with Fn::Join and Ref for AWS::AccountId, AWS::Region, or AWS::URLSuffix. Compare deployment behavior with an equivalent hard-coded image value; done means updating the referenced image triggers an AWS::CodeDeploy::BlueGreen deployment.

Written by the indexing model from the issue text.