chore(sns): kms key is not deleted in integ.sns.ts (#29664)

### Issue # (if applicable)

Closes #29663

### Reason for this change

kms key created within integ test remains after integ test.

### Description of changes

Added "pendingWindow" and "removalPolicy" to kms resource.



```ts
    const key = new Key(this, 'CustomKey', {
      pendingWindow: Duration.days(7),
      removalPolicy: RemovalPolicy.DESTROY,
    });
```

### Description of how you validated changes

I confirmed with integ test that it works as expected.

### Checklist
- [ ] 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: jun1-t

packages/@aws-cdk-testing/framework-integ/test/aws-sns/test/integ.sns.js.snapshot/SNSInteg.assets.json

@@ -30,10 +30,11 @@
       }
      ],
      "Version": "2012-10-17"
-    }
+    },
+    "PendingWindowInDays": 7
    },
-   "UpdateReplacePolicy": "Retain",
-   "DeletionPolicy": "Retain"
+   "UpdateReplacePolicy": "Delete",
+   "DeletionPolicy": "Delete"
   },
   "MyTopic86869434": {
    "Type": "AWS::SNS::Topic",

packages/@aws-cdk-testing/framework-integ/test/aws-sns/test/integ.sns.js.snapshot/SNSInteg.template.json

@@ -1,13 +1,16 @@
 import { Key } from 'aws-cdk-lib/aws-kms';
-import { App, Stack, StackProps } from 'aws-cdk-lib';
+import { App, Stack, StackProps, RemovalPolicy, Duration } from 'aws-cdk-lib';
 import { LoggingProtocol, Topic } from 'aws-cdk-lib/aws-sns';
 import { ManagedPolicy, PolicyDocument, PolicyStatement, Role, ServicePrincipal } from 'aws-cdk-lib/aws-iam';
 
 class SNSInteg extends Stack {
   constructor(scope: App, id: string, props?: StackProps) {
     super(scope, id, props);
 
-    const key = new Key(this, 'CustomKey');
+    const key = new Key(this, 'CustomKey', {
+      pendingWindow: Duration.days(7),
+      removalPolicy: RemovalPolicy.DESTROY,
+    });
 
     const topic = new Topic(this, 'MyTopic', {
       topicName: 'fooTopic',