game_ui doesn't fire left/right inputs when playing on a controller

[vrad-exe]

When the player is using a controller, the game_ui entity won't fire outputs for when the player presses left/right, only forward/backward. This entity is commonly used by mappers to detect player inputs, so the bug results in workshop maps such as Re-Invigorated being unplayable on Steam Deck or otherwise when keyboard controls are not available.

Within SDK 2013, this code in in_main.cpp seems like it might be the culprit: if joystick input is enabled and the forward move value is greater than or less than 0, it sets the foward/back buttons respectively as pressed, but it doesn't do the same for left/right. game_ui then checks the player's pressed buttons to see what outputs it should fire, so it would never see left/right as pressed and wouldn't fire those.