Core/Creatures: Fix battleground spirit guides on ffa pvp realms

Closes #31438

Author: Shauren

src/server/game/Entities/Creature/Creature.cpp

@@ -639,6 +639,13 @@ bool Creature::UpdateEntry(uint32 entry, CreatureData const* data /*= nullptr*/,
 
     m_stringIds[AsUnderlyingType(StringIdType::Template)] = &cInfo->StringId;
 
+    if (IsSpiritGuide() && sWorld->IsFFAPvPRealm())
+    {
+        // client will only send spirit guide query for units that can assist them
+        // for ffa pvp flagged players its only other ffa pvp flagged units
+        SetPvpFlag(UNIT_BYTE2_FLAG_FFA_PVP);
+    }
+
     return true;
 }