fix(DB/Creatures): Nat Pagle should display vendor icon if player completed Nat's Measuring Tap quest. (#10657)

Moved c++ script to DB. Original author: @offl
Fixes #10559

src/server/game/Entities/Player/Player.cpp

@@ -13806,6 +13806,20 @@ bool Player::CanSeeSpellClickOn(Creature const* c) const
     return false;
 }
 
+bool Player::CanSeeVendor(Creature const* creature) const
+{
+    if (!creature->HasFlag(UNIT_NPC_FLAGS, UNIT_NPC_FLAG_VENDOR))
+        return true;
+
+    ConditionList conditions = sConditionMgr->GetConditionsForNpcVendorEvent(creature->GetEntry(), 0);
+    if (!sConditionMgr->IsObjectMeetToConditions(const_cast<Player*>(this), const_cast<Creature*>(creature), conditions))
+    {
+        return false;
+    }
+
+    return true;
+}
+
 void Player::BuildPlayerTalentsInfoData(WorldPacket* data)
 {
     *data << uint32(GetFreeTalentPoints());                 // unspentTalentPoints

src/server/game/Entities/Player/Player.h

@@ -2490,6 +2490,7 @@ public:
 
     //bool isActiveObject() const { return true; }
     bool CanSeeSpellClickOn(Creature const* creature) const;
+    [[nodiscard]] bool CanSeeVendor(Creature const* creature) const;
 
     [[nodiscard]] uint32 GetChampioningFaction() const { return m_ChampioningFaction; }
     void SetChampioningFaction(uint32 faction) { m_ChampioningFaction = faction; }