↔ [Converter] Add support for `aten::Int.Tensor` in Torch-TensorRT TorchScript Path

## aten::Int.Tensor

- **Function Schema**: `aten::Int.Tensor(Tensor a) -> int`

- **Original PyTorch API**: torch.item() [[documentation](https://pytorch.org/docs/stable/generated/torch.Tensor.item.html)]

This converter/evaluator extracts the integer value from single-element tensors.
