chore(secrets): bump semanticVersion for aws-cn (aws#30201)

### Issue # (if applicable)

Similar to aws#28733 , this PR bumps the default version for aws-cn partition ro `1.1.237` as the current version comes with deprecated lambda python runtime.

```
aws --profile bjs serverlessrepo get-application --application-id arn:aws-cn:serverlessrepo:cn-north-1:193023089310:applications/SecretsManagerRDSPostgreSQLRotationSingleUser --query Version.SemanticVersion --output text
1.1.237
```

I was evaluating a fix for aws#30200 but unfortunately that would require a lot of refactor so I am opening this tiny PR to get it bumped.

internal tracking: P128811127





Closes #<issue number here>.

### Reason for this change



### Description of changes



### 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)

### How to find the serverless `applicationId` and `semanticVersion`
1. Go to the serverlessrepo console and search `SecretsManagerRDSPostgreSQLRotationSingleUser`. Make sure to check `Show apps that create custom IAM roles or resource policies`

<img width="434" alt="image" src="https://github.com/aws/aws-cdk/assets/278432/f3fbd9e8-64b0-4c84-b877-dc5bdef1e9f8">


2. Click into the application
3. Find the `applicationId` from the URL. For example, in `us-east-1` the id is
`arn:aws:serverlessrepo:us-east-1:297356227824:applications/SecretsManagerRDSPostgreSQLRotationSingleUser`
4. Find out the semanticVersion using AWS CLI:

```sh
$ appid='arn:aws:serverlessrepo:us-east-1:297356227824:applications/SecretsManagerRDSPostgreSQLRotationSingleUser'
$ aws serverlessrepo get-application --application-id $appid --query Version.SemanticVersion --output text
```
----

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

packages/@aws-cdk-testing/framework-integ/test/aws-docdb/test/integ.cluster-rotation.lit.js.snapshot/aws-cdk-docdb-cluster-rotation.template.json

@@ -695,7 +695,7 @@
    },
    "aws-cn": {
     "applicationId": "arn:aws-cn:serverlessrepo:cn-north-1:193023089310:applications/SecretsManagerMongoDBRotationSingleUser",
-    "semanticVersion": "1.1.212"
+    "semanticVersion": "1.1.237"
    },
    "aws-us-gov": {
     "applicationId": "arn:aws-us-gov:serverlessrepo:us-gov-west-1:023102451235:applications/SecretsManagerMongoDBRotationSingleUser",