### 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
return find_api_subentity_by_id(api_id, authorizer_id, "authorizers")
def normalize_authorizer(data):
    is_list = isinstance(data, list)
    entries = data if is_list else [data]
    for i in range(len(entries)):
        entry = common.clone(entries[i])
        
        entry["authorizerResultTtlInSeconds"] = int(entry.get("authorizerResultTtlInSeconds", 300))
        entries[i] = entry
    return entries if is_list else entries[0]
def get_authorizers(path):
    region_details = APIGatewayRegion.get()
    
    api_id = get_api_id_from_path(path)
    authorizer_id = get_authorizer_id_from_path(path)
    auth_list = region_details.authorizers.get(api_id) or []
    if authorizer_id:
        authorizer = _find_authorizer(api_id, authorizer_id)
        if authorizer is None:
            return make_error_response(
                "Authorizer not found: %s" % authorizer_id,
                code=404,
                error_type="NotFoundException",
            )
        return to_authorizer_response_json(api_id, authorizer)
    result = [to_authorizer_response_json(api_id, a) for a in auth_list]
    result = {"item": result}
    return result
def add_authorizer(path, data):