### 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
invocation_context: ApiInvocationContext,
) -> ApiInvocationContext:
    
    values = (
        invocation_context.api_id,
        invocation_context.stage,
        invocation_context.path_with_query_string,
    )
    if all(values):
        return invocation_context
    
    if invocation_context.is_websocket_request():
        return invocation_context
    path = invocation_context.path
    headers = invocation_context.headers
    path_match = re.search(PATH_REGEX_USER_REQUEST, path)
    host_header = headers.get(HEADER_LOCALSTACK_EDGE_URL, "") or headers.get("Host") or ""
    host_match = re.search(HOST_REGEX_EXECUTE_API, host_header)
    test_invoke_match = re.search(PATH_REGEX_TEST_INVOKE_API, path)
    if path_match:
        api_id = path_match.group(1)
        stage = path_match.group(2)
        relative_path_w_query_params = "/%s" % path_match.group(3)
    elif host_match:
        api_id = extract_api_id_from_hostname_in_url(host_header)
        stage = path.strip("/").split("/")[0]