Fix aspect ratio heuristics getting stuck to a state

[Filoppi]

Fix aspect ratio heuristics getting stuck to widescreen (or to non widescreen) (m_is_game_widescreen variable) if the user first forced the aspect ratio to 16:9/4:3 and then set it back to Auto.

This specifically happens in games 2D main menus, which have no 3D graphics so the aspect ratio heuristics fail to determine whether the game was widescreen or not. The behaviour can be replicated in The Legend of Zelda: Four Swords Adventures 60Hz mode.

Video showcasing the problem: https://github.com/dolphin-emu/dolphin/assets/7011366/fad3c4e3-ba1b-4c09-89f4-976ec3fac3d1