### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

Authorization headers being sent to API gateway are received on lambdas as "empty string"

### Expected Behavior

_No response_

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

Run a API Gateway with lambda integration

### Environment

```markdown
- OS:
- LocalStack:
```


### Anything else?

_No response_
return aws_stack.get_region()
    @classmethod
    def get_current_request_account_id(cls) -> str:
        return get_aws_account_id()
    @classmethod
    def reset(cls):
        """Reset the (in-memory) state of this service region backend."""
        cls.initialise()
        cls.REGIONS = {}
        account_id = cls.get_current_request_account_id()
        cls._ACCOUNT_BACKENDS[account_id] = {}
def append_cors_headers(
    request_headers: Dict = None, response: Union[Response, LambdaResponse] = None
):
    
    if config.DISABLE_CORS_HEADERS:
        return
    
    headers = {} if response is None else response.headers
    
    
    
    if isinstance(response, LambdaResponse):
        for key in response.multi_value_headers.keys():
            headers_list = list(response.multi_value_headers[key]) + [response.headers.get(key)]
            headers_list = [str(h) for h in headers_list if h is not None]
            headers[key] = ",".join(headers_list)
        response.multi_value_headers = {}
    if ACL_ORIGIN not in headers: