### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

APiGateway Model that being created by CDK project stores the JSON schema with a single quotes instead of double quotes which leading to an error in parsing this json object. 

you can refere to this article to see the steps 

https://dev.to/dvddpl/reduce-lambda-invocations-and-code-boilerplate-by-adding-a-json-schema-validator-to-your-api-gateway-15af

and it works fine on AWS account 

also you can look on the attached image how localstack stores the JSON object with a single quotes, I tried to edit it manually through UI but it return it back with single quotes

![Screen Shot 2022-10-18 at 4 28 08 PM](https://user-images.githubusercontent.com/106184681/196769273-0834865a-2fb3-4efc-b3a9-9da6b2ad511d.png)

### Expected Behavior

store the json schema in correct JSON format

### How are you starting LocalStack?

With the `localstack` script

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

    localstack start

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

    cdklocal deploy


### Environment

```markdown
- OS:OSX
- LocalStack: 1.0.4
```


### Anything else?

_No response_
self, context: RequestContext, client_certificate_id: String
    ) -> None:
        region_details = get_apigateway_store()
        entity = region_details.client_certificates.pop(client_certificate_id, None)
        if entity is None:
            raise NotFoundException(f'VPC link ID "{client_certificate_id}" not found for deletion')
    
    def create_vpc_link(
        self,
        context: RequestContext,
        name: String,
        target_arns: ListOfString,
        description: String = None,
        tags: MapOfStringToString = None,
    ) -> VpcLink:
        region_details = get_apigateway_store()
        link_id = short_uid()
        entry = {"id": link_id, "status": "AVAILABLE"}
        region_details.vpc_links[link_id] = entry
        result = to_vpc_link_response_json(entry)
        return VpcLink(**result)
    def get_vpc_links(