### 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_
# recr
        url = presigned_client.generate_presigned_url(
            "put_", Params={"Bucket": s3_bucket, "Key": key}
        )
        assert "x-amz-content-sha256" not in url
        # asse
        resp = .put(
            url,
            data="something",
            verify=False,
            headers={"x-amz-content-sha256": "UNSIGNED-PAYLOAD"},
        )
        assert resp.ok
        # asse
        resp = .put(
            url, data="something", verify=False, headers={"x-amz-user-agent": "test"}
        )
        assert resp.status_code == 403
        # X-Am
        index = url.find("&X-Amz-Signature")
        rewritten_url = url[:index] + "&x-id=Pu" + url[index:]
        # howe
        resp = .put(rewritten_url, data="something", verify=False)
        assert resp.status_code == 403
class TestS3DeepArchive:
    """
    Test to cover DEEP_ARCHIVE Storage Class functionality.
    """
    @markers.aws.validated
    def test_storage_class_deep_archive(self, s3_bucket, tmpdir, aws_client):