chore(cli): fix integ test (#8323)

Attempt #2 
our diff command represents the URLSuffix (typically amazonaws.com)
by using the CloudFormation pseudo-parameter.

modifies the principal in the test to expect it instead. ran tests locally.

----

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

@@ -437,15 +437,15 @@ test('IAM diff', async () => {
 
   // Roughly check for a table like this:
   //
-  // ┌───┬─────────────────┬────────┬────────────────┬────────────────────────────┬───────────┐
-  // │   │ Resource        │ Effect │ Action         │ Principal                  │ Condition │
-  // ├───┼─────────────────┼────────┼────────────────┼────────────────────────────┼───────────┤
-  // │ + │ ${SomeRole.Arn} │ Allow  │ sts:AssumeRole │ Service:ec2.amazonaws.com  │           │
-  // └───┴─────────────────┴────────┴────────────────┴────────────────────────────┴───────────┘
+  // ┌───┬─────────────────┬────────┬────────────────┬────────────────────────────-──┬───────────┐
+  // │   │ Resource        │ Effect │ Action         │ Principal                     │ Condition │
+  // ├───┼─────────────────┼────────┼────────────────┼───────────────────────────────┼───────────┤
+  // │ + │ ${SomeRole.Arn} │ Allow  │ sts:AssumeRole │ Service:ec2.${AWS::URLSuffix} │           │
+  // └───┴─────────────────┴────────┴────────────────┴───────────────────────────────┴───────────┘
 
   expect(output).toContain('${SomeRole.Arn}');
   expect(output).toContain('sts:AssumeRole');
-  expect(output).toContain('ec2.amazonaws.com');
+  expect(output).toContain('ec2.${AWS::URLSuffix}');
 });
 
 test('fast deploy', async () => {