Handle trust-constr callback state arg in ScipyMinimize

[Whning0513]

Summary

• accept SciPy callback state arguments in ScipyMinimize._run() instead of assuming every method calls callback(xk)
• add a focused regression test covering the trust-constr callback shape that passes (xk, state)

Testing

• python -m pytest -q tests/scipy_wrappers_callback_test.py

I only ran the focused regression test here because this environment does not have the full jax test stack installed.

Fixes #636.