### 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_
assert StorageClass.STANDARD in presigned_url
        assert "bar-complicated-no-random" in presigned_url
        # miss
        response = .put(presigned_url, verify=False, data=b"123456")
        assert response.status_code == 403
        # AWS 
        # but 
        response = .put(
            presigned_url,
            data=b"123456",
            verify=False,
            headers={"Content-MD5": "4QrcOUm6Wau+VuBX8g+IPg=="},
        )
        assert response.status_code == 200
        # veri
        head_ = aws_client.s3.head_(Bucket=function_name, Key=_key)
        snapshot.match("head-", head_)
    @pytest.mark.skipif(condition=TEST_S3_IMAGE, reason="Lambda not enabled in S3 image")
    @markers.aws.validated
    def test_presigned_url_v4_signed_headers_in_qs(
        self,
        s3_bucket,
        s3_create_bucket,
        patch_s3_skip_signature_validation_false,
        create_lambda_function,
        lambda_su_role,
        create_tmp_folder_lambda,
        aws_client,
    ):
        # test