Regenerate test model with ONNX IR < 12 (#26149)
### Description
- Regenerates the `input_propagate_to_output.onnx` model used in [this
unit
test](https://github.com/microsoft/onnxruntime/blob/35dcab5088118117acc6086c9b6dd6dd92c7060f/onnxruntime/test/shared_lib/test_inference.cc#L497-L506)
so that it uses an ONNX IR version compatible with ONNX 1.18.0 (i.e., IR
version < 12).
- Adds script `input_propagate_to_output.py` that can be used to
regenerate the `input_propagate_to_output.onnx` model.
- Embed missing weight values that are needed to run the existing
`test_dangling_input_segment_ids.py` script.
### Motivation and Context
The main branch is using ONNX 1.19. However, this unit test also needs
to pass in the `rel-1.23.1` branch, which is still using ONNX 1.18.0.
So, by downgrading the model's IR version, the unit test can run in both
branches.
See original PR that added the test models:
https://github.com/microsoft/onnxruntime/pull/26021
