Fix false-positive 'broken quest log' error on WotLK servers

GetQuestObjectives returns nil for quests with no trackable objectives
on WotLK private servers. The original code set hasInvalidObjective=true
but left isQuestLogGood=true, causing goodQuestsCount to stay 0 while
numQuests was 19 -> 'Good quest: 0/19' error on every login/reload.

Treat a non-table return as an empty valid objective list. Demote the
Questie:Error to Questie:Debug so it doesn't spam chat.

Modules/QuestieValidateGameCache.lua

@@ -92,10 +92,10 @@ local function OnQuestLogUpdate()
                 local objectiveList = GetQuestObjectives(questId, i)
 
                 if type(objectiveList) ~= "table" then
-                    -- I couldn't find yet a quest returning nil like older code suggested for example for quest 2744, which isn't true.
+                    -- On WotLK private servers, GetQuestObjectives can return nil for quests with
-                    -- I guess older code queried data before HaveQuestData() was true.
+                    -- no trackable objectives. This is not a broken cache state; treat it as an
-                    Questie:Error("REPORT THIS ERROR! Quest objectives aren't a table. This may stop Questie from loading. questId =", questId)
+                    -- empty (valid) objective list so goodQuestsCount increments correctly.
-                    hasInvalidObjective = true
+                    Questie:Debug(Questie.DEBUG_DEVELOP, "[QuestieValidateGameCache] GetQuestObjectives returned non-table for questId:", questId, "- treating as empty objectives")
                     objectiveList = {}
                 end