Core/EscortAI: std::chrono-ify SetPauseTimer

(cherry picked from commit cdaf890af4)

src/server/scripts/Northrend/zone_borean_tundra.cpp

@@ -1621,7 +1621,7 @@ public:
                 _events.ScheduleEvent(EVENT_TALK_1, Seconds(2));
                 _events.CancelEvent(EVENT_OOC_TALK);
                 Start(true, true, player->GetGUID());
-                SetPauseTimer(12 * IN_MILLISECONDS);
+                SetPauseTimer(12s);
             }
         }