docs(dynamodb): fix doc for awsManagedKey method (aws#31649)

### Issue # (if applicable)

Closes #<issue number here>.

### Reason for this change



The doc for `awsManagedKey` method is wrong.

- Configure server-side encryption using **a DynamoDB owned** key.

### Description of changes



Fixed.

- Configure server-side encryption using **an AWS managed** key.

### Description of how you validated changes



### Checklist
- [x] 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)

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

packages/aws-cdk-lib/aws-dynamodb/lib/encryption.ts

@@ -26,7 +26,7 @@ export abstract class TableEncryptionV2 {
   }
 
   /**
-   * Configure server-side encryption using a DynamoDB owned key.
+   * Configure server-side encryption using an AWS managed key.
    */
   public static awsManagedKey(): TableEncryptionV2 {
     return new (class extends TableEncryptionV2 {