fix(events-targets): hardcoded AWS partition in ECS task resource ARN (#29633)

### Issue # (if applicable)

Closes #29610 

Related to #28898

### Reason for this change

Previously the AWS partition was hardcoded so it would not work for other special partitions.

### Description of changes

Replace hardcoded `aws` partition to be dynamically added with `this.cluster.stack.partition`. 

### Description of how you validated changes

Ran integ tests suite, no changes. 

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: paulhcsun

packages/@aws-cdk-testing/framework-integ/test/aws-ecs-patterns/test/ec2/integ.scheduled-ecs-task.js.snapshot/aws-ecs-integ-ecs.assets.json

@@ -918,7 +918,11 @@
         "Fn::Join": [
          "",
          [
-          "arn:aws:ecs:",
+          "arn:",
+          {
+           "Ref": "AWS::Partition"
+          },
+          ":ecs:",
           {
            "Ref": "AWS::Region"
           },