### 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
"""Custom boto3 session that points to local endpoint URLs."""
    def resource(self, service, *args, **kwargs):
        self._fix_endpoint(kwargs)
        return connect_to_resource(service, *args, **kwargs)
    def client(self, service, *args, **kwargs):
        self._fix_endpoint(kwargs)
        return connect_to_service(service, *args, **kwargs)
    def _fix_endpoint(self, kwargs):
        if "amazonaws.com" in kwargs.get("endpoint_url", ""):
            kwargs.pop("endpoint_url")
def get_boto3_session(cache=True):
    if not cache or CREATE_NEW_SESSION_PER_BOTO3_CONNECTION:
        return boto3.session.Session()
    
    return boto3
def get_region():
    
    from localstack.utils.aws.request_context import get_region_from_request_context
    region = get_region_from_request_context()
    if region:
        return region
    
    return get_local_region()
def get_partition(region_name: str = None):
    region_name = region_name or get_region()
    return boto3.session.Session().get_partition_for_region(region_name)
def get_local_region():