* Ensure tensors use default device in torch policy and utils

---------

Co-authored-by: maryam-zia <[email protected]>

This change corrects the tensor indexing calculation in TensorExtensions.Index()
to properly support CHW (channels-height-width) format used by both Unity's
observation writers and ONNX models during inference.

* Update Changelog

* Update tests

…t breaking onnx changes in torch 2.9.0 (#6251)

* Pin torch version to 2.8.0 to prevent breaking onnx changes in 2.9.0

The ` 2.9.0` version results in an issue finding `onnxscript`. Pinning the `2.8.0` prevent this error. 

I'm not exactly of the exact root cause but it seems there were some backwards incompatible changes to onnx: https://github.com/pytorch/pytorch/releases/tag/v2.9.0#backwards-incompatible-changes.

Stack trace on exiting training:
```
  File "C:\Users\Samuel\miniconda3\envs\mlagents\lib\site-packages\mlagents\trainers\torch_entities\model_serialization.py", line 164, in export_policy_model
    torch.onnx.export(
  File "C:\Users\Samuel\miniconda3\envs\mlagents\lib\site-packages\torch\onnx\__init__.py", line 282, in export
    from torch.onnx._internal.exporter import _compat
  File "C:\Users\Samuel\miniconda3\envs\mlagents\lib\site-packages\torch\onnx\_internal\exporter\_compat.py", line 16, in <module>
    from torch.onnx._internal.exporter import (
  File "C:\Users\Samuel\miniconda3\envs\mlagents\lib\site-packages\torch\onnx\_internal\exporter\_core.py", line 18, in <module>
    import onnxscript
ModuleNotFoundError: No module named 'onnxscript'
```

* Add torch version constraint to be equal or less than 2.8.0

Previously commit forced only 2.8.0, however adding this constraint is a bit nicer, as I see in some of installation docs sometimes torch 2.2.0 is installed: https://github.com/Unity-Technologies/ml-agents/blob/release_22_docs/docs/Installation.md.

* Update CHANGELOG.md

* Update com.unity.ml-agents/Documentation~/Installation.md
---------

Co-authored-by: manugaursharma <[email protected]>

* Test macos code signing for binaries
* Adding dependency on signing job in pack

* Upgrade Inference Engine to 4.1.1
* Update inference engine dependencies
* Update CHANGELOG.md
* trunk test are unstable changing to 6.3 temporarily
* Fixing issue #6268

Co-authored-by: maryam-zia <[email protected]>