fix error in monster update hook

The training hall dummy seems to not have a "SetInfo" property, so we
add a check for this to avoid crashing in the monster update hook when
in the training hall. This fixes an issue where poison and blast damage
was not being tracked in the training hall.

src/autorun/mhrise-coavins-dps.lua

@@ -2911,15 +2911,17 @@ local function updateBossEnemy(args)
 
 	if not boss.id then
 		local setInfo = enemy:call("get_SetInfo")
-		local id = setInfo:call("get_UniqueId")
-		if id then
-			log_info('found id ' .. id .. ' for ' .. boss.name)
-			if id == 0 then
-				id = FAKE_ATTACKER_ID
-				log_info('override id to ' .. id)
-			end
+		if setInfo then
+			local id = setInfo:call("get_UniqueId")
+			if id then
+				log_info('found id ' .. id .. ' for ' .. boss.name)
+				if id == 0 then
+					id = FAKE_ATTACKER_ID
+					log_info('override id to ' .. id)
+				end
 
-			boss.id = id
+				boss.id = id
+			end
 		end
 	end