Update libeffect.cpp

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

libeffect.cpp

@@ -271,11 +271,8 @@ int32_t scriptlib::effect_set_category(lua_State *L) {
 	check_param_count(L, 2);
 	check_param(L, PARAM_TYPE_EFFECT, 1);
 	effect* peffect = *(effect**) lua_touserdata(L, 1);
-	int64_t v = lua_tointeger(L, 2);
-	if(v < 0) {
-		return luaL_error(L, "Parameter 2 should be non-negative.");
-	}
-	peffect->category = (uint64_t)v;
+	uint64_t v = (uint64_t)lua_tointeger(L, 2);
+	peffect->category = v;
 	return 0;
 }
 int32_t scriptlib::effect_set_hint_timing(lua_State *L) {