### 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_
# dele
        aws_client.s3.delete_bucket_analytics_configuration(
            Bucket=bucket,
            Id=storage_analysis["Id"],
        )
        response = aws_client.s3.list_bucket_analytics_configurations(Bucket=bucket)
        snapshot.match("list_config_with_storage_analysis_2", response)
    @markers.aws.validated
    def test_s3_intelligent_tier_config(self, aws_client, s3_create_bucket, snapshot):
        bucket = s3_create_bucket()
        intelligent_tier_configuration = {
            "Id": "test1",
            "Filter": {
                "Prefix": "test1",
            },
            "Status": "Enabled",
            "Tierings": [
                {"Days": 90, "AccessTier": "ARCHIVE_ACCESS"},
            ],
        }
        # diff
        with pytest.raises(ClientError) as put_err_1:
            aws_client.s3.put_bucket_intelligent_tiering_configuration(
                Bucket=bucket,
                Id="incorrect_id",
                IntelligentTieringConfiguration=intelligent_tier_configuration,
            )
        snapshot.match(
            "put_bucket_intelligent_tiering_configuration_err_1`", put_err_1.value.response
        )