### 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_
download_file_ = to_str(downloaded_["Body"].read())
        assert len(body) == len(str(download_file_))
        assert body == str(download_file_)
    @markers.aws.only_localstack
    @pytest.mark.skipif(
        reason="Not implemented in other providers than stream",
        condition=LEGACY_V2_S3_PROVIDER,
    )
    def test_put__chunked_newlines_with_checksum(self, s3_bucket, aws_client, region_name):
        # Boto 
        # aws_
        # Test 
        _key = "data"
        body = "Hello Blob"
        valid_checksum = hash_sha256(body)
        headers = {
            "Authorization": mock_aws_request_headers(
                "s3",
                aws_access_key_id=TEST_AWS_ACCESS_KEY_ID,
                region_name=region_name,
            )["Authorization"],
            "Content-Type": "audio/mpeg",
            "X-Amz-Content-Sha256": "STREAMING-AWS4-HMAC-SHA256-PAYLOAD-TRAILER",
            "X-Amz-Date": "20190918T051509Z",
            "X-Amz-Decoded-Content-Length": str(len(body)),
            "x-amz-sdk-checksum-algorithm": "SHA256",
            "x-amz-trailer": "x-amz-checksum-sha256",
            "Content-Encoding": "aws-chunked",
        }
        def get_data(content: str, checksum_value: str) -> str: