### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

Sending a message with body:
`"&quot;&quot;"`
is received on the consumer side with body:
`""""`

### Expected Behavior

Sending a message with body:
"&quot;&quot;"
is received on the consumer side with body:
"&quot;&quot;"

### 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`)

Running localstack in docker desktop on Mac using helm chart

https://localstack.github.io/helm-charts
version 0.3.7
Image version: 0.14.3

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



### Environment

```markdown
- OS: macOS Monterey
- LocalStack: 0.14.3
```


### Anything else?

_No response_
: str
    ) -> HttpResponse:
        """
        Serializes a given response dict (the return payload of a service implementation) to an _event stream_ using the
        given operation model.
        :param response: dictionary containing the payload for the response
        :param operation_model: describing the operation the response dict is being returned by
        :param mime_type: Mime type which should be used to encode the payload
        :return: HttpResponse which can directly be sent to the client (in chunks)
        """
        event_stream_shape = operation_model.get_event_stream_output()
        event_stream_member_name = operation_model.output_shape.event_stream_name
        # wrap the generator in operation specific serialization
        def event_stream_serializer() -> Iterable[bytes]:
            yield _event_payload("initial-response")
            # yield convert_to_binary_event_payload("", event_type="initial-response")
            # create a default response
            serialized_event_response = self._create_default_roperation_model, mime_type)
            # get the members of the event stream shape
            event_stream_shape_members = (
                event_stream_shape.members if event_stream_shape is not None else None
            )
            # extract the generator from the given response data
            event_generator = response.get(event_stream_member_name)
            if not isinstance(event_generator, Iterator):
                raise ProtocolSerializerError(
                    "Expected iterator for streaming event serialization."
                )
            # yield one event per generated event
            for event in event_generator:
                # find the actual event payload (the member with event=true)
                event_member_shape = None
                event_member_name = None
                for member_name, member_shape ers.items():
                    if member_shape.serialization.get("event") and membe