devel/py-mime: Mark IGNORE on python 3.12 and later

Fails at stage-qa:
Error: Python package installs top-level 'tests/' directory in site-packages
Error: Location: lib/python3.12/site-packages/tests
Error: This causes file conflicts with other packages. Exclude it via
pyproject.toml:
Error: [tool.setuptools.packages.find]
Error: exclude = ["tests", "tests.*"]

Given the inactivity of the upstream for the last 10 years IGNORE is
better than BROKEN

Approved by: portmgr (blanket)