### 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_
USERS: List[str] = []  # `USERS` is common across regions and defined+initialised as class attribute
            order: Dict[str, str]  # `order` is specific to a region and declared as instance attribute
            def __init__(self):
                self.order = {}  # `order` must be initialised
    Limitations
    ===========
    - Do not add new staticmethods/classmethods to subclasses. This causes issues with deepcopy
    """
    
    _ACCOUNTS_CLS: Dict[str, Type[T]]
    
    _ACCOUNT_BACKENDS: DefaultDict[str, Dict[str, T]]
    
    REGIONS: Dict[str, T]
    name: str  
    account_id: str  
    @classmethod
    def get(cls: Type[T], region: str = None, account_id: str = None) -> T:
        cls.initialise()
        region = region or cls.get_current_request_region()
        account_id = account_id or cls.get_current_request_account_id()
        
        
        
        
        
        if MULTI_ACCOUNTS and account_id not in cls._ACCOUNTS_CLS:
            
            data = {k: v for k, v in cls.__dict__.items() if not inspect.ismethoddescriptor(v)}
            cls_dict = copy.deepcopy(data)