Scripts/GameObjects: fixed visuals for Firework gameobjects

sql/updates/world/custom/custom_2019_04_09_03_world.sql

@@ -0,0 +1 @@
+UPDATE `gameobject_template` SET `ScriptName`= 'go_generic_firework' WHERE `entry` BETWEEN 180720 AND 180741;

src/server/scripts/World/go_scripts.cpp

@@ -1905,6 +1905,16 @@ public:
     }
 };
 
+struct go_generic_firework : public GameObjectAI
+{
+    go_generic_firework(GameObject* go) : GameObjectAI(go) { }
+
+    void InitializeAI() override
+    {
+        me->DespawnOrUnsummon(Milliseconds(urandms(10, 30)), 6s);
+    }
+};
+
 void AddSC_go_scripts()
 {
     new go_cat_figurine();
@@ -1946,4 +1956,5 @@ void AddSC_go_scripts()
     new go_darkmoon_faire_music();
     new go_pirate_day_music();
     new go_bells();
+    RegisterGameObjectAI(go_generic_firework);
 }