In the Portal game on my Steam Deck, how do I set up my controller so pressing the left stick forward and back moves the character forward and back and pressing the left stick left and right makes my character turn, and pressing the right stick left and right makes my character strafe and pressing the right stick up and down makes me look up and down? In other words, I want to swap the left and right functions of the left and right sticks while leaving the up and down functions alone. How do I do this?