EventsRuleToSns - Cloudwatch Event does not deliver message when enableEncryptionWithCustomerManagedKey is false

In `EventsRuleToSns`, if you set `enableEncryptionWithCustomerManagedKey` to false, the Cloudwatch Event fails to deliver its message to the SNS Topic.

### Reproduction Steps

```
new EventsRuleToSns(this, 'EventsRuleToSns', {
topicsProps: { topicName: 'my-topic' },
eventRuleProps: {
schedule: Schedule.rate(Duration.minutes(1)),
},
enableEncryptionWithCustomerManagedKey: false,
})
```

### Error Log

There's no error message

### Environment

- **CDK CLI Version :1.93.0
- **CDK Framework Version:1.93.0
- **AWS Solutions Constructs Version :1.93.0
- **OS :Ubuntu 20 LTS
- **Language :Typescript

### Other
See https://stackoverflow.com/a/66357234/8400466 for an explanation.

A possible fix can be to include the option to disable at rest encryption all together

---

This is :bug: Bug Report

Start with the EventsRuleToSns construct and reproduce the configuration shown with enableEncryptionWithCustomerManagedKey set to false. Trace how the event rule, SNS topic, and encryption settings are configured, then verify that the scheduled event delivers a message without requiring a customer-managed key.

Written by the indexing model from the issue text.