### 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
if not is_api_key_valid(api_key_required, headers, invocation_context.stage):
        return make_error_response("Access denied - invalid API key", 403)
    integrations = resource.get("resourceMethods", {})
    integration = integrations.get(method, {})
    if not integration:
        
        
        integration = integrations.get("ANY", {}) or integrations.get(
            "X-AMAZON-APIGATEWAY-ANY-METHOD", {}
        )
    integration = integration.get("methodIntegration")
    if not integration:
        if method == "OPTIONS" and "Origin" in headers:
            
            return get_cors_response(headers)
        return make_error_response(
            "Unable to find integration for: %s %s (%s)" % (method, invocation_path, raw_path),
            404,
        )
    res_methods = resource.get("resourceMethods", {})
    meth_integration = res_methods.get(method, {}).get("methodIntegration", {})
    int_responses = meth_integration.get("integrationResponses", {})
    response_templates = int_responses.get("200", {}).get("responseTemplates", {})
    
    invocation_context.resource = resource
    invocation_context.resource_path = extracted_path
    invocation_context.response_templates = response_templates
    invocation_context.integration = integration
    return invoke_rest_api_integration(invocation_context)
def invoke_rest_api_integration(invocation_context: ApiInvocationContext):