eks: Configuring target role for Pod Identity

### Describe the feature

When running applications on Amazon Elastic Kubernetes Service (Amazon EKS), you might need to access AWS resources that exist in different AWS accounts.

### Use Case

Pod Identity enables applications in your EKS cluster to access AWS resources across accounts through a process called role chaining.

When creating a Pod Identity association, you can provide two IAM roles: an [EKS Pod Identity role](https://docs.aws.amazon.com/eks/latest/userguide/pod-id-role.html) in the same account as your EKS cluster and a Target IAM Role from the account containing your AWS resources you wish to access, (like S3 buckets or RDS Databases). The [EKS Pod Identity role](https://docs.aws.amazon.com/eks/latest/userguide/pod-id-role.html) must be in your EKS cluster’s account due to [IAM PassRole](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_iam-passrole-service.html) requirements, while the Target IAM Role can be in any AWS account. PassRole enables an AWS entity to delegate role assumption to another service. EKS Pod Identity uses PassRole to connect a role to a Kubernetes service account, requiring both the role and the identity passing it to be in the same AWS account as the EKS cluster. When your application pod needs to access AWS resources, it requests credentials from Pod Identity. Pod Identity then automatically performs two role assumptions in sequence: first assuming the [EKS Pod Identity role](https://docs.aws.amazon.com/eks/latest/userguide/pod-id-role.html), then using those credentials to assume the Target IAM Role. This process provides your pod with temporary credentials that have the permissions defined in the target role, allowing secure access to resources in other AWS accounts.

### Proposed Solution

Add the support for the new Target IAM role field

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### AWS CDK Library version (aws-cdk-lib)

2.210.0

### AWS CDK CLI version

2.1024.0

### Environment details (OS name and version, etc.)

macOS

Start by locating the EKS Pod Identity association construct and the AWS API or CloudFormation model it wraps, then inspect existing tests for association properties and role validation. Done means the association accepts and synthesizes the Target IAM Role for cross-account role chaining, with tests covering the new field.

Written by the indexing model from the issue text.