Fix Arrow failing to detect quest completion fallback

When QuestLogCache parses incomplete tracker data upon reload,
it leaves quest.isComplete undefined or false. This allows the
Arrow to process SpecialObjectives (like required source item drops)
which do not have Completed/Needed/Collected stats on them, bypassing
our recent arrow logic fix.

Added an explicit check for QuestieDB.IsComplete(quest.Id) == 1
at the very top of the track loop to guarantee the Arrow immediately
stops processing objectives and exclusively targets the finisher.

Modules/Arrow/QuestieArrow.lua

@@ -437,7 +437,8 @@ function QuestieArrow:UpdateNearestTargets()
         end
 
         -- If the quest is complete, track the finisher/turn-in location
-        if quest.isComplete then
+        if quest.isComplete or QuestieDB.IsComplete(quest.Id) == 1 then
+            quest.isComplete = true
             local function _GetCompleteIconType()
                 local iconType = Questie.ICON_TYPE_COMPLETE
                 if QuestieDB and QuestieDB.IsActiveEventQuest and QuestieDB.IsActiveEventQuest(quest.Id) then