world conquest: fix bezoar artifact being bugged (#6515)

changelog.md

@@ -2,6 +2,8 @@
  ### Add-ons client
  ### Add-ons server
  ### Campaigns
+   * World Conquest
+     * Fixed Bezoar artifact being bugged and broken.
  ### Editor
  ### Multiplayer
  ### Lua API

data/campaigns/World_Conquest/lua/game_mechanics/artifacts.lua

@@ -114,6 +114,14 @@ function artifacts.give_item(unit, index, visualize)
 	unit:add_modification("object", object)
 	--rebuild unit, to reduce savefile size.
 	unit:transform(unit.type)
+
+	-- slot in traits if any artifacts grant any
+	for trait in wml.child_range(artifacts.list[index], "trait") do
+		if not unit:matches { wml.tag.filter_wml { wml.tag.modifications { wml.tag.trait { id = trait.id } } } } then
+			unit:add_modification("trait", trait)
+		end
+	end
+
 	-- restore unit hitpoints to before they picked up the artifact
 	unit.hitpoints = unit_initial_hp
 	-- the artifact might reduce the max xp.