drop --no-python-version-warning from pip install

[miguelinux]

When using hatch sell with pip 25.0.1 at the first time, a deprecation warning is showed:

$ hatch shell
DEPRECATION: --no-python-version-warning is deprecated. pip 25.1 will
enforce this behaviour change. A possible replacement is to remove the
flag as it's a no-op. Discussion can be found at
pypa/pip#13154
You are about to enter a new shell, exit as you usually would e.g. by
typing exit or pressing ctrl+d...

Looking at pypa/pip#13154 it said:

The Python 2 days are behind us, thus we can kill off the
--no-python-version-warning flag which disabled the
"Python 2 is sunsetting support" warnings :)

If you're using this flag, you can simply stop. It does nothing today.

So, lets remove it to not show the warning

[djcopley]

Dup of #1913