* Cadidate selection check assignment

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>

* Review fixes

* Punish collator for wrong announcements

* Update node/core/candidate-selection/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>