### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

- Localstack fails with HTTP 500, error code "InternalError", message "not enough values to unpack (expected 2, got 1)" when `CopySource` is an invalid string for `copy_object` API.

### Expected Behavior

- For the same API `copy_object`, the cloud fails with HTTP 400, error code "InvalidArgument".
- Localstack should handle invalid `CopySource` i.e., it is a dictionary with one value or an invalid string not adhering to "{bucket}/{key}" format.

### How are you starting LocalStack?

With a `docker run` command

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

    docker run localstack/localstack

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

    botoclient.copy_object(CopySource="Invalid_random_string", Bucket="test_bucket", Key=key) 


 test_bucket is a valid bucket.  

### Environment

```markdown
- OS: Ubuntu 22.04.2 LTS
- LocalStack: 2.1.0
- boto3: 1.28.6
```


### Anything else?

_No response_
with pytest.raises(ClientError) as e:
            lfc["Rules"] = [
                {
                    "Expiration": {"Days": 7},
                    "ID": "wholebucket",
                    "Status": "Enabled",
                }
            ]
            aws_client.s3.put_bucket_lifecycle_configuration(
                Bucket=s3_bucket, LifecycleConfiguration=lfc
            )
        snapshot.match("missing-filter", e.value.response)
        with pytest.raises(ClientError) as e:
            lfc["Rules"] = [
                {
                    "Expiration": {"Days": 7},
                    "Filter": {},
                    "ID": "wholebucket",
                    "Status": "Enabled",
                    "NoncurrentVersionExpiration": {},
                    # No N
                }
            ]
            aws_client.s3.put_bucket_lifecycle_configuration(
                Bucket=s3_bucket, LifecycleConfiguration=lfc
            )
        snapshot.match("missing-noncurrent-version-expiration-data", e.value.response)
        with pytest.raises(ClientError) as e:
            lfc["Rules"] = [
                {