“The discretion not to enforce an offer to settle is to be exercised on a case by case basis and only rarely and in the presence of compelling circumstances: Yonge Village Recreation Centre Limited v. York Condominium Corporation No. 201, 2007 CanLII 36647 (ON SCDC), 229 O.A.C. 144 (Div. Ct.), adopted by Hashemi-Sabet Estate v. Oak Ridges Pharmasave Inc., 2018 ONCA 839, at para. 39.”