### 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_
table_name = data["GlobalTableName"]
    if table_name in DynamoDBRegion.GLOBAL_TABLES:
        return get_error_message(
            "Global Table with this name already exists",
            "GlobalTableAlreadyExistsException",
        )
    DynamoDBRegion.GLOBAL_TABLES[table_name] = data
    for group in data.get("ReplicationGroup", []):
        group["ReplicaStatus"] = "ACTIVE"
        group["ReplicaStatusDescription"] = "Replica active"
    result = {"GlobalTableDescription": data}
    return result
def describe_global_table(data):
    table_name = data["GlobalTableName"]
    details = DynamoDBRegion.GLOBAL_TABLES.get(table_name)
    if not details:
        return get_error_message(
            "Global Table with this name does not exist", "GlobalTableNotFoundException"
        )
    result = {"GlobalTableDescription": details}
    return result
def list_global_tables(data):
    result = [
        select_attributes(tab, ["GlobalTableName", "ReplicationGroup"])
        for tab in DynamoDBRegion.GLOBAL_TABLES.values()
    ]
    result = {"GlobalTables": result}
    return result
def update_global_table(data):