fix: enable storageEncrypted option for vector store

[drskur]

Issue #, if available:

Description of changes:
enable storageEncrypted for vector store

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[statefb]

@drskur Thank you for your contribution!
Encryption itself is an important feature, so I'm very grateful for it. However, if user run cdk deploy as is, the RDS will be replaced, which would be a destructive change for existing users. Therefore, I believe it is essential to have a migration guide, such as restoring from a snapshot. Could you please add a Markdown document with the steps outlined? It would also be extremely helpful if you could confirm that the data stored before and after following these steps is the same.
Please also include encryption for DynamoDB (this can be done by adding one line, and no migration is required).
Thank you for your assistance with this request.

[jeremylatorre]

I agree for DynamoDB, message encryption should be a must have. I'm a little bit concerned about performance issues by adding encryption in vectorStore.