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# Type of request: This is a ...

[x] bug report
[ ] feature request

# Detailed description

When running with dynamodb errors set to 1.0 and performing basically any kind of request, I see the following in the console: 

```
localstack_main | 2021-01-22T22:14:37:WARNING:localstack.utils.server.http2_server: Error in proxy handler for request POST http://localhost:4566/: 'ProxyListenerDynamoDB' object has no attribute 'error_response_throughput' Traceback (most recent call last):
localstack_main |   File "/opt/code/localstack/localstack/utils/server/http2_server.py", line 107, in index
localstack_main |     raise result
localstack_main |   File "/opt/code/localstack/localstack/utils/bootstrap.py", line 581, in run
localstack_main |     result = self.func(self.params)
localstack_main |   File "/opt/code/localstack/localstack/utils/async_utils.py", line 28, in _run
localstack_main |     return fn(*args, **kwargs)
localstack_main |   File "/opt/code/localstack/localstack/services/generic_proxy.py", line 605, in handler
localstack_main |     response = modify_and_forward(method=method, path=path_with_params, data_bytes=data, headers=headers,
localstack_main |   File "/opt/code/localstack/localstack/services/generic_proxy.py", line 373, in modify_and_forward
localstack_main |     listener_result = listener.forward_request(method=method,
localstack_main |   File "/opt/code/localstack/localstack/services/edge.py", line 105, in forward_request
localstack_main |     return do_forward_request(api, method, path, data, headers, port=port)
localstack_main |   File "/opt/code/localstack/localstack/services/edge.py", line 116, in do_forward_request
localstack_main |     result = do_forward_request_inmem(api, method, path, data, headers, port=port)
localstack_main |   File "/opt/code/localstack/localstack/services/edge.py", line 136, in do_forward_request_inmem
localstack_main |     response = modify_and_forward(method=method, path=path, data_bytes=data, headers=headers,
localstack_main |   File "/opt/code/localstack/localstack/services/generic_proxy.py", line 373, in modify_and_forward
localstack_main |     listener_result = listener.forward_request(method=method,
localstack_main |   File "/opt/code/localstack/localstack/services/dynamodb/dynamodb_listener.py", line 97, in forward_request
localstack_main |     return self.error_response_throughput()
localstack_main | AttributeError: 'ProxyListenerDynamoDB' object has no attribute 'error_response_throughput'
```

which seems like a mistake. It looks like we get one of those for every request.

## Expected behavior

I wouldn't expect the console to print anything

# Steps to reproduce

I made #3501 to simplify reproduction. Basically just pull that, pull the latest docker image, run `./example/run.sh`.

## Command used to start LocalStack

`docker-compose up`
req = {'TableName': table_name, 'Key': search_key}
    existing_item = aws_stack.dynamodb_get_item_raw(req)
    if not existing_item:
        return existing_item
    if 'Item' not in existing_item:
        if 'message' in existing_item:
            table_names = ddb_client.list_tables()['TableNames']
            msg = ('Unable to get item from DynamoDB (existing tables: %s ...truncated if >100 tables): %s' %
                (table_names, existing_item['message']))
            LOGGER.warning(msg)
        return
    return existing_item.get('Item')
def get_error_message(message, error_type):
    response = error_response(message=message, error_type=error_type)
    fix_headers_for_updated_response(response)
    return response
def get_table_not_found_error():
    return get_error_message(message='Cannot do operations on a non-existent table',
                             error_type='ResourceNotFoundException')
def fix_headers_for_updated_response(response):
    response.headers['Content-Length'] = len(to_bytes(response.content))
    response.headers['x-amz-crc32'] = calculate_crc32(response)
def update_put_item_response_content(data, response_content):
    
    
    
    if data.get('ReturnValues'):
        response_content = json.dumps({'Attributes': data['Item']})
    return response_content
def calculate_crc32(response):