### 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_
"""An exception indicating that a region could not be matched to a partition."""
    arn_regex = re.compile(
        r"arn:"  
        r"(?P<Partition>(aws|aws-cn|aws-iso|aws-iso-b|aws-us-gov)*):"  
        r"(?P<Service>[\w-]*):"  
        r"(?P<Region>[\w-]*):"  
        r"(?P<AccountID>[\w-]*):"  
        r"(?P<ResourcePath>"  
        r"((?P<ResourceType>[\w-]*)[:/])?"  
        r"(?P<ResourceID>[\w\-/*]*)"  
        r")"
    )
    def forward_request(