chore(aws-cdk-testing): fix integ test case using unrestricted princi…

…pal for role

This test case is flagged up by automated security tooling.
There is no actual risk since this is a test stack that is only short-lived and the permissions for the role only allow consuming messages from a queue that doesn't hold any data.

packages/@aws-cdk-testing/cli-integ/resources/cdk-apps/simple-app/app.js

@@ -14,7 +14,7 @@ class SimpleStack extends cdk.Stack {
       visibilityTimeout: cdk.Duration.seconds(300),
     });
     const role = new iam.Role(this, 'role', {
-      assumedBy: new iam.AnyPrincipal(),
+      assumedBy: new iam.AccountRootPrincipal(),
     });
     queue.grantConsumeMessages(role);
   }