Refactor Executorch bindings

[msluszniak]

Description

Refactor Executorch bindings to pass to ExecutorchModule.forward Tensor instead of separate ETInput and shape.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update (improves or adds clarity to existing documentation)

Tested on

• iOS
• Android

Testing instructions

Use ExecutorchModule.forward with new workflow.

Screenshots

Not applicable

Related issues

#209

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes

[chmjkb]

Hey, thanks for submitting this PR! I need to close it since we're completely rewriting this API as part of our broader C++ migration effort. You can track the progress in #345. We may incorporate some of your documentation changes though! 😄