Fix FileNotFoundError at startup

Hello, I'm not sure the commit format is correct as I've never contributed to Arch before but this fixes the gaupol package which is broken at the moment. The patch I added comes from https://bugs.gentoo.org/839267 where I faced the same issue on Gentoo.

Without this patch, aeidon/paths.py contains:

DATA_DIR = '/gaupol-1.15.data/data/share/gaupol'
LOCALE_DIR = '/gaupol-1.15.data/data/share/locale'

This causes gaupol to fail at startup:

Traceback (most recent call last):
  File "/usr/bin/gaupol", line 16, in <module>
    import gaupol
  File "/usr/lib/python3.12/site-packages/gaupol/__init__.py", line 69, in <module>
    from gaupol import style # noqa
    ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/gaupol/style.py", line 28, in <module>
    with open(CSS_FILE, "r") as f:
         ^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '/gaupol-1.15.data/data/share/gaupol/ui/gaupol.css'