math/py-numdifftools: Fix USE_PYTHON=pytest usage

• Use TEST_ARGS instead of PYTEST_ARGS
• While I'm here, add missing TEST_DEPENDS

ERRORS

___________ ERROR collecting src/numdifftools/tests/test_scripts.py ___________
ImportError while importing test module '/wrkdirs/usr/ports/math/py-numdifftools/work-py312/numdifftools-0.11.1/src/numdifftools/tests/test_scripts.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/usr/local/lib/python3.12/importlib/__init__.py:90: in import_module

return _bootstrap._gcd_import(name[level:], package, level)
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/numdifftools/tests/test_scripts.py:1: in <module>

from numdifftools import run_benchmark

src/numdifftools/run_benchmark.py:7: in <module>

import matplotlib.pyplot as plt

E ModuleNotFoundError: No module named 'matplotlib'

short test summary info

SKIPPED [1] src/numdifftools/tests/test_profile_numdifftools.py:3: could not import 'profiletools': No module named 'profiletools'
!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!

1 skipped, 1 error in 1.28s

• Error code 2

Approved by: portmgr (blanket)
With hat: python