[rcore][RGFW] Fix mg_gamepads_free() iterating freed list nodes

[robknopf]

The for loop in mg_gamepads_free() captured cur->prev before calling mg_gamepad_release(). If the release mutated or freed the node, the next iteration would follow a stale pointer. Changed to a while loop that reads gamepads->list.cur fresh each iteration.

[raysan5]

@robknopf I'm afraid this reeview should be implemented in RGFW repo or it will be override when updating the library