Avoid divide by zero in vehicle::print_fuel_indicator

Cap can be zero on wrecks, so it's important we check for it.

Fixes #64407

src/vehicle_display.cpp

@@ -453,7 +453,7 @@ void vehicle::print_fuel_indicator( const catacurses::window &win, const point &
             rate += power_to_energy_bat( net_battery_charge_rate( /* include_reactors = */ true ), 1_hours );
             units = _( "kJ" );
         }
-        if( rate != 0 ) {
+        if( rate != 0 && cap != 0 ) {
             int tank_use = 0;
             nc_color tank_color = c_light_green;
             std::string tank_goal = _( "full" );