(codepipeline_actions): CodeDeployEcsDeployAction doesn't return the role created by default

### What is the problem?

If you create a CodeDeployEcsDeployAction and don't pass a role as a parameter, the codepipeline will generate a default one for you (as seen in [pipeline.ts](https://github.com/aws/aws-cdk/blob/7966f8d48c4bff26beb22856d289f9d0c7e7081d/packages/%40aws-cdk/aws-codepipeline/lib/pipeline.ts#L573)). However this role cannot be retrieved from the CodeDeployEcsDeployAction object.

### Reproduction Steps

```ts
const deploymentGroup = codedeploy.EcsDeploymentGroup.fromEcsDeploymentGroupAttributes(stack, "DeploymentGroup", {
application: EcsApplication.fromEcsApplicationName(stack, "ECSApplication", "test"),
deploymentGroupName: "test",
});

const action = new codepipeline_actions.CodeDeployEcsDeployAction({
actionName: "Deploy",
deploymentGroup: deploymentGroup,
taskDefinitionTemplateInput: new codepipeline.Artifact("dummy"),
appSpecTemplateInput: new codepipeline.Artifact("dummy2"),
});

const pipeline = new codepipeline.Pipeline(stack, "Pipeline", {
stages: [
{
stageName: "DeployECS",
actions: [action],
},
],
});

const actionRole = action.actionProperties.role;
// actionRole is always undefined
console.log(actionRole);
```

### What did you expect to happen?

`action.actionProperties.role` returns the default role created by codepipeline.

### What actually happened?

`action.actionProperties.role` is undefined.

### CDK CLI Version

1.129.0

### Framework Version

_No response_

### Node.js Version

14.18.1

### OS

Amazon Linux 2

### Language

Typescript

### Language Version

_No response_

### Other information

_No response_

Start with the linked pipeline.ts code and the CodeDeployEcsDeployAction entry point, then trace how action.actionProperties.role is populated when no role is supplied. Reproduce the example and confirm that the generated default role is exposed through action.actionProperties.role.

Written by the indexing model from the issue text.