### 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_
private_key = key.private_bytes(
        crypto_serialization.Encoding.DER,
        crypto_serialization.PrivateFormat.PKCS8,
        crypto_serialization.NoEncryption(),
    )
    public_key = key.public_key().public_bytes(crypto_serialization.Encoding.DER, public_format)
    cipher_text_blob = None
    if create_cipher:
        cipher_text = kms.encrypt(KeyId=key_id, Plaintext=private_key)["CiphertextBlob"]
        cipher_text_blob = base64.b64encode(cipher_text)
    region = region_details.get_current_request_region()
    result = {
        "PrivateKeyCiphertextBlob": cipher_text_blob,
        "PrivateKeyPlaintext": base64.b64encode(private_key),
        "PublicKey": base64.b64encode(public_key),
        "KeyId": key_id,
        "KeyPairSpec": key_spec,
        "KeySpec": key_spec,
        "KeyUsage": "SIGN_VERIFY",
        "Policy": data.get("Policy"),
        "Region": region,
        "Description": data.get("Description"),
        "Arn": aws_stack.kms_key_arn(key_id),
        "_key_": key,
    }
    region_details.key_pairs[key_id] = result
    key = Key("", result["KeyUsage"], key_spec, result["Description"], region)
    key.id = key_id
    return {**key.to_dict()["KeyMetadata"], **result}
def set_key_managed(key_id: str) -> None: