Spearhead API updates (#31)

Co-authored-by: dutchie032 <dutchie032>

classes/stageClasses/missions/ZoneMission.lua

@@ -289,7 +289,7 @@ end
 
 function ZoneMission:SpawnPersistedState()
     for _, group in pairs(self._missionGroups.groups) do
-        group:SpawnCorpsesOnly()
+        group:Spawn()
     end
 end
 

classes/stageClasses/missions/baseMissions/Mission.lua

@@ -113,6 +113,11 @@ function Mission:NotifyMissionComplete()
             listener:OnMissionComplete(self)
         end)
     end
+
+    pcall(function()
+        Spearhead.API.Internal.notifyMissionComplete(self.zoneName)
+    end)
+
 end
 
 ---endregion