### 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_
if self.checksum is None:
            self.checksum = zlib.crc32(value)
            return
        self.checksum = zlib.crc32(value, self.checksum)
    def digest(self) -> bytes:
        return self.checksum.to_bytes(4, "big")
class ObjectRange(NamedTuple):
    """
    NamedTuple representing a parsed Range header with the requested S3 object size
    https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Range
    """
    content_range: str  
    content_length: int  
    begin: int  
    end: int  
def parse_range_header(range_header: str, object_size: int) -> ObjectRange | None:
    """
    Takes a Range header, and returns a dataclass containing the necessary information to return only a slice of an
    S3 object. If the range header is invalid, we return None so that the request is treated as a regular request.
    :param range_header: a Range header
    :param object_size: the requested S3 object total size
    :return: ObjectRange or None if the Range header is invalid
    """
    last = object_size - 1
    try:
        _, rspec = range_header.split("=")
    except ValueError:
        return None
    if "," in rspec: