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# Type of request: This is a ...

[x] bug report
[ ] feature request

# Detailed description

SNS is unable to forward the message to SQS (non fifo queue) when using the `elasticmq` backend and fails with the following log
```
2021-01-19T09:31:50:WARNING:localstack.services.sns.sns_listener: Unable to forward SNS message to SQS: An error occurred (InvalidParameterValue) when calling the SendMessage operation: Value for parameter MessageGroupId is invalid. The request include parameter that is not valid for this queue type Traceback (most recent call last):

File "/opt/code/localstack/localstack/services/sns/sns_listener.py", line 297, in message_to_subscribers

sqs_client.send_message(

File "/opt/code/localstack/.venv/lib/python3.8/site-packages/botocore/client.py", line 357, in _api_call

return self._make_api_call(operation_name, kwargs)

File "/opt/code/localstack/.venv/lib/python3.8/site-packages/botocore/client.py", line 676, in _make_api_call

raise error_class(parsed_response, operation_name)

botocore.exceptions.ClientError: An error occurred (InvalidParameterValue) when calling the SendMessage operation: Value for parameter MessageGroupId is invalid. The request include parameter that is not valid for this queue type
```
This is likely a regression due to #3435. Tested with the default backend on `0.12.5` and it works as expected. Also works with `elasticmq` backend on `0.12.4`

## Expected behavior

Same behavior with the `elasticmq` backend as with the default backend.

## Actual behavior

Fails on `elasticmq` backend, no SQS message received when SNS message is sent.

# Steps to reproduce

## Command used to start LocalStack

```yaml
  localstack:
    image: localstack/localstack:0.12.5
    ports:
      - 4566:4566
    environment:
      - AWS_DEFAULT_REGION=ap-northeast-1
      - SERVICES=sns,sqs
      - SQS_PROVIDER=elasticmq
```

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

return make_error(code=400, code_string='InvalidParameter', message='Subject')
                
                
                if 'PhoneNumber' not in req_data and 'TargetArn' not in req_data:
                    if topic_arn not in SNS_SUBSCRIPTIONS:
                        return make_error(code=404, code_string='NotFound', message='Topic does not exist')
                message_id = publish_message(topic_arn, req_data)
                
                return make_response(req_action, message_id=message_id)
            elif req_action == 'ListTagsForResource':
                tags = do_list_tags_for_resource(topic_arn)
                content = '<Tags/>'
                if len(tags) > 0:
                    content = '<Tags>'
                    for tag in tags:
                        content += '<member>'
                        content += '<Key>%s</Key>' % tag['Key']
                        content += '<Value>%s</Value>' % tag['Value']
                        content += '</member>'
                    content += '</Tags>'
                return make_response(req_action, content=content)
            elif req_action == 'CreateTopic':
                topic_arn = aws_stack.sns_topic_arn(req_data['Name'][0])
                tag_resource_success = self._extract_tags(topic_arn, req_data, True)
                SNS_SUBSCRIPTIONS[topic_arn] = SNS_SUBSCRIPTIONS.get(topic_arn) or []
                
                if not tag_resource_success:
                    return make_error(code=400, code_string='InvalidParameter',
                                  message='Topic already exists with different tags')
            elif req_action == 'TagResource':