### 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_
"ID": rule_id_2,
                    "Filter": {
                        "And": {
                            "Tags": [
                                {
                                    "Key": "testlifecycle",
                                    "Value": "positive",
                                },
                                {
                                    "Key": "testlifecycletwo",
                                    "Value": "positive-two",
                                },
                            ],
                        },
                    },
                    "Status": "Enabled",
                    "Expiration": {"Days": current_exp_days},
                },
            ]
        }
        aws_client.s3.put_bucket_lifecycle_configuration(
            Bucket=s3_bucket, LifecycleConfiguration=lfc
        )
        result = aws_client.s3.get_bucket_lifecycle_configuration(Bucket=s3_bucket)
        snapshot.match("get-bucket-lifecycle-conf", result)
        key_match_1 = "test-expiry"
        tag_set_match = "testlifecycle=positive&testlifecycletwo=positivetwo"
        put_ = aws_client.s3.put_(
            Body=b"test", Bucket=s3_bucket, Key=key_match_1, Tagging=tag_set_match
        )