fix: input controls being applied to ai players.

[tzemanovic]

fixes #722

I'm still getting familiar with the code, but it looks like what's happening is that when you press the Grab/Drop key on Keyboard 2, the input sometimes makes the AI player drop the sword and when it has enough velocity it gets insta-killed by collision detection (this I think is related to #714). I was able to reproduce this issue in a local game only.

After some digging, I found that this seems to be caused the session's input being propagated to all the player inputs including the AIs in a local session (when network_player_idx.is_some()). Removing the condition skips the loop for AI players locally and still works in a network game, where each local player has player_idx = 0.

[zicklag]

Awesome, thank you! I'll try to check this out when I get the chance.

@lecoqjacob I requested your review, in case you want to and you can get to checking this out before me. Nevermined, it didn't let me request your review, but if you want to check this out feel free. :)

[bayou-brogrammer]

In the scenario where we have AI players in an online session, does this break that rule?

[zicklag]

We actually don't let you have AI in an online match at the moment. Still we'll probably want that so we might want to code defensively and assume that it could happen.

[tzemanovic]

Yeah, I think this will still work with AI players in an online session because their input is being controlled elsewhere (fn player_ai_system)

[zicklag]

Sounds good, mering! Thank you!