Support for torch.linalg.lstsq operation

## ❓Question about torch.linalg.lstsq Operation Support

### Summary
I am attempting to convert a PyTorch model that uses `torch.linalg.lstsq` to CoreML using `coremltools`, but it seems that this operation is not supported as well as other torch.linalg ops

### Issue Details
When I try to convert my model, I get an error stating that `torch.linalg` is unsupported. This is causing significant issues as there doesn't seem to be a straightforward workaround.

### Version
coremltools 7.1 [Latest](https://github.com/apple/coremltools/releases/latest)

### Code Sample
```
ref, residuals, rank, singular_values = torch.linalg.lstsq(
A_regul * weights_regul, b_regul * weights_regul)
```

Start by reproducing the conversion failure from the provided torch.linalg.lstsq example with coremltools 7.1, then trace the converter's handling of torch.linalg operations. Done means the example converts successfully and the supported operation is covered by conversion validation; no file or test location is identified in the issue.

Written by the indexing model from the issue text.