### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

When attempting to sign some document using Localstack KMS inside a lambda container (also running on localstack), the localstack KMS listener returns some unknown error.

The KMS key and lambda containers have been created from the same CDK app deploy, and I can see all the resources in the localstack web console.

The test application I'm using to prove this behaviour is available here:
https://github.com/LukaHedt/localstack_kms_test

Instructions to run are in the main Readme, and the `/localstack/Readme.md` file.

`aws-sdk` returns an unknown error, and the localstack docker logs that I receive are available here:
https://pastebin.com/58Z3fXi3

Have done an amount of testing and can confidently claim the following:
- Have tested on multiple machines with the same outcome
- Doesn’t make a difference if I specify an ARN or a KeyID in the signing request
- Downgrading localstack versions either didn’t make a difference, or I couldn’t actually deploy a localstack container with version 0.12.20 or lower.

### Expected Behavior

KMS Sign should return a signature for the given payload.

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

Test application demonstrating the current behaviour is available here:

https://github.com/LukaHedt/localstack_kms_test

Full instructions to run are in the `/localstack/Readme.md` file.


### Environment

```markdown
- OS: MacOS Monteray 12.3
- LocalStack: 0.14.0
```


### Anything else?

_No response_
"""
    Sets a KMS key to AWS managed
    :param key_id: ID of the KMS key
    """
    region_name = aws_stack.get_region()
    backend = kms_backends.get(region_name)
    key_data = backend.keys.get(key_id)
    if key_data:
        key_data.key_manager = "AWS"
def create_key(data: Dict):
    key_usage = data.get("KeyUsage")
    if key_usage != "SIGN_VERIFY" or KMS_PROVIDER == "local-kms":
        return
    data["KeyId"] = long_uid()
    result = _generate_data_key_pair(data, create_cipher=False)
    result = {"KeyMetadata": json_safe(result)}
    return result
def sign(data, response):
    region_details = KMSBackend.get()
    response.status_code = 200
    algo = data.get("SigningAlgorithm")
    key_id = data.get("KeyId")
    message = base64.b64decode(to_bytes(data.get("Message")))
    key_pair = region_details.key_pairs.get(key_id)