### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

Currently the VTL template for `request_templates` is not processed properly:

```
#set( $body = $input.json("$") )

#macro( loop $map )
{
    #foreach($key in $map.keySet())
        #set( $k = $util.escapeJavaScript($key) )
        #set( $v = $util.escapeJavaScript($map.get($key)).replaceAll("\\'", "'") )
        "$k": "$v"
        #if( $foreach.hasNext ) , #end
    #end
}
#end

{
    "enhancedAuthContext": #loop($context.authorizer),

    "headers": #loop($input.params().header),

    "query": #loop($input.params().querystring),

    "path": #loop($input.params().path),

    "identity": #loop($context.identity),

    "stageVariables": #loop($stageVariables),
}
EOF
}
```

results in,

```
'

{
    "enhancedAuthContext": {
    }
,

    "headers": {
    }
,

    "query": {
    }
,

    "path": {
    }
,

    "identity": {
    }
,

    "stageVariables": {
    }
,
}
'
```

### Expected Behavior

The template should be rendered and have the JSON properties.

### How are you starting LocalStack?

Custom (please describe below)

### Steps To Reproduce

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

    docker run localstack/localstack

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

    awslocal s3 mb s3://mybucket


### Environment

```markdown
- OS: MacOS
- LocalStack: 0.14
```


### Anything else?

This example can be used to validate.
https://github.com/localstack/localstack-terraform-samples/tree/master/apigateway-lambda-velocity
)
        response_configs = [
            {"pattern": "^2.*", "code": success_code, "res_templates": res_templates},
            {"pattern": "^4.*", "code": client_error_code, "res_templates": {}},
            {"pattern": "^5.*", "code": server_error_code, "res_templates": {}},
        ]
        
        for response_config in response_configs:
            
            client.put_integration_response(
                restApiId=api_id,
                resourceId=resource_id,
                httpMethod=method["httpMethod"],
                statusCode=response_config["code"],
                responseTemplates=response_config["res_templates"],
                selectionPattern=response_config["pattern"],
            )
            
            client.put_method_response(
                restApiId=api_id,
                resourceId=resource_id,
                httpMethod=method["httpMethod"],
                statusCode=response_config["code"],
            )
def apigateway_invocations_arn(lambda_uri, region_name: str = None):
    return "arn:aws:apigateway:%s:lambda:path/2015-03-31/functions/%s/invocations" % (
        region_name or get_region(),
        lambda_uri,
    )
def get_opensearch_endpoint(domain_arn: str) -> str: