Let CalculatedImpactChance return early to avoid unnecessarily hitting OvulationChance

1.4/source/RJW_Menstruation/RJW_Menstruation/HediffComps/HediffComp_Menstruation.cs

@@ -322,6 +322,7 @@ namespace RJW_Menstruation
                 // Implant factor will be based solely on pawn age, plus any rollover from ovulation chance
                 float factor = 1.0f;
                 StatDefOf.Fertility.GetStatPart<StatPart_FertilityByGenderAge>()?.TransformValue(StatRequest.For(Pawn), ref factor);
+                if (factor <= 0.0f) return 0.0f;
                 if (OvulationChance > 1.0f) factor *= OvulationChance;
                 return Props.baseImplantationChanceFactor * FertilityModifier * factor;
             }