python-pip: bump to 26.2.1

python-pip: bump to 26.2.1

Refresh sha256 from the PyPI sdist and refresh 003 for the shifted line.

Retarget 002-pip-runner-pyc-fix.patch instead of dropping it: in 26.2.1
get_runnable_pip() moved from build_env.py (now a package) to
_internal/utils/misc.py. The function is otherwise unchanged and still
returns __pip-runner__.py, so the .pyc fallback is still required. We ship
pip byte-compiled only (the .py sources live in the -src package), so
without it build isolation cannot locate the runner and every PEP 517
install fails on target. This is a packaging workaround, not an upstream
bug, so upstream has no reason to carry it.

Signed-off-by: Alexandru Ardelean <redacted>