Relax constraint for onnxruntime for the python package

[reyammer]

There is a known limitation in uv that forces us to add a constraint to which onnxruntime version we can use in the python module. At first I thought the limitation was fixed, but that's not the case.

Here is more context so that, when this is fixed on uv size, we remember to relax the onnxruntime constraint.

To reproduce:

$ uv init --python 3.9
$ uv add onnxruntime
[...]
error: Distribution `onnxruntime==1.20.1 @ registry+https://pypi.org/simple` can't be installed because it doesn't have a source distribution or wheel for the current platform

• Our initial fix: Add constraint for onnxruntime for the python package #801
• The uv issue I opened: uv add onnxruntime currently fails on MacOS astral-sh/uv#9228
• Another uv issue (with which the first one was merged): uv add rejects pytorch from its index when on mac astral-sh/uv#5182
• uv's fix for the second issue: Backtrack to non-local versions when wheels are missing platform support astral-sh/uv#10046 (Source: uv add rejects pytorch from its index when on mac astral-sh/uv#5182 (comment)). But it turns out that the fix only addressed the second issue, not mine.
• uv's onnxruntime-related open issue: uv add onnxruntime fails to fetch latest version of package compatible with my environment's Python astral-sh/uv#9425
• uv's tracking issue for the overall problem: Tracking issue: package without source distribution gets an "incomplete" resolution astral-sh/uv#9711

Suggestion on how to fix in the meantime: astral-sh/uv#9425 (comment), which is what we implemented in #926.