Reduce the complexity of linear_algebra/src/polynom_for_points.py (#7948)

* updating DIRECTORY.md

* updating DIRECTORY.md

* updating DIRECTORY.md

* Lower the --max-complexity threshold in the file .flake8

* Reduce the complexity of linear_algebra/src/polynom_for_points.py

* Update linear_algebra/src/polynom_for_points.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Update linear_algebra/src/polynom_for_points.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Fix

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>