Vehicle weapons not manually fireable in remote drive in Single Player

[zig1000]

The `shoot selected` (default: shift+space) control does not work while driving a vehicle in remote view, UNLESS the save is or has been a multiplayer save (distinguishable by the presence of a `Weapons control` toggle in the vehicle GUI - in single player, only the `Auto targeting` section exists). Tested with Spidertron + rockets.

This for example makes it hard to terraform lava on Vulcanus remotely, with the only alternative I'm aware of being driving a tank or car into a reactor.