Check if tech is null in show_tech_gained_dialog.
Check if tech is null in show_tech_gained_dialog.

andreasrosdal/freeciv-web,adaxi/freeciv-web,tltneon/freeciv-web,andreasrosdal/freeciv-web,adaxi/freeciv-web,andreasrosdal/freeciv-web,andreasrosdal/freeciv-web,tltneon/freeciv-web,adaxi/freeciv-web,tltneon/freeciv-web,tltneon/freeciv-web,tltneon/freeciv-web,tltneon/freeciv-web,andreasrosdal/freeciv-web,adaxi/freeciv-web,adaxi/freeciv-web