RTMO head deployment fix for non-square input sizes

[jvasi]

Fixes the RTMO pose output during ONNX conversion for models with non-symmetrical input dimensions.

Motivation

RTMO deployment of models with custom input image size break during deployment.

Modification

The feature maps were incorrectly following an [N, C, W, H] format. This change ensures the dimensions are correctly transposed to [N, C, H, W].

This issue was previously masked when using symmetrical input resolutions (e.g., 640x640) where H and W are interchangeable, but caused output breakage for rectangular aspect ratios.

BC-breaking

No changing breaks to the backward compatibility as far as I am aware.

Use cases

No new use-cases

Checklist

Before PR:

• I have read and followed the workflow indicated in the CONTRIBUTING.md to create this PR.
• Pre-commit or linting tools indicated in CONTRIBUTING.md are used to fix the potential lint issues.
• Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
• New functionalities are covered by complete unit tests. If not, please add more unit tests to ensure correctness.
• The documentation has been modified accordingly, including docstring or example tutorials.

After PR:

• CLA has been signed and all committers have signed the CLA in this PR.

[CLAassistant]

All committers have signed the CLA.