chore(cli): fix integ test for IAM diff (#8316)

following on from #8274 where a broken integ test that never ran was fixed.
A different test for the IAM diff was verifying previously incorrect service
principal and we missed updating the expectation.

This fixes up the expectations to align to the changes made in #8274 and
uses the corrected service principal (ec2.amazonaws.com).

----

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

packages/aws-cdk/test/integ/cli/cli.integtest.ts

@@ -440,12 +440,12 @@ test('IAM diff', async () => {
   // ┌───┬─────────────────┬────────┬────────────────┬────────────────────────────┬───────────┐
   // │   │ Resource        │ Effect │ Action         │ Principal                  │ Condition │
   // ├───┼─────────────────┼────────┼────────────────┼────────────────────────────┼───────────┤
-  // │ + │ ${SomeRole.Arn} │ Allow  │ sts:AssumeRole │ Service:ec2.amazon.aws.com │           │
+  // │ + │ ${SomeRole.Arn} │ Allow  │ sts:AssumeRole │ Service:ec2.amazonaws.com  │           │
   // └───┴─────────────────┴────────┴────────────────┴────────────────────────────┴───────────┘
 
   expect(output).toContain('${SomeRole.Arn}');
   expect(output).toContain('sts:AssumeRole');
-  expect(output).toContain('ec2.amazon.aws.com');
+  expect(output).toContain('ec2.amazonaws.com');
 });
 
 test('fast deploy', async () => {