[Python] CI build should run the same flake8/autopep8 checks as commit hooks

[tellarin]

It seems if users don't have the hooks setup, they can still create PRs and lint issues are not captured in build. This leads to issues where future pushes from users that do have the correct hooks in place are blocked by spurious issues.

CI build should run the same checke, to avoid such issues being introduced into the repo in the first place.