Remove PrefersNonDefaultGPU from the desktop file

[Jan200101]

ValveSoftware/steam-for-linux#9940

originally added by #3
they key is unreliable and tends to break desktop setups

same was done for the flatpak package flathub/com.valvesoftware.Steam@fdbd21c

a longer explanation on why its broken can be found here
https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/5PUGDWKQJQ7LZNAUXAINVITTNWWGZKN7/

[mmstick]

PrefersNonDefaultGPU is widely used by many applications, and likewise supported by major DEs. It works as intended on Pop!_OS.

[Jan200101]

Sadly it does not work as intended on Pop!_OS because it inherited the logic from Gnome which has a flawed implementation.

I have an open merge request to gnome-shell that would resolve this
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3193

[mmstick]

I'm not sure what issue you're having. We do test Steam on both desktops and hybrid graphics laptops.

[Jan200101]

The issue that happens is that PrefersNonDefaultGPU will make the application launch with the Non-Default GPU which in the case of a Desktop will likely be the integrated GPU.

This isn't a special case either and happens to quite a few people who take the time to figure things out

ValveSoftware/steam-for-linux#8179
ValveSoftware/steam-for-linux#8983
ValveSoftware/steam-for-linux#9383
ValveSoftware/steam-for-linux#8276
ValveSoftware/steam-for-linux#10929
flathub/com.valvesoftware.Steam#784
linuxmint/cinnamon#10699
https://bugs.kde.org/show_bug.cgi?id=480797

Steam is a very notable case here because of its tendency to crash when used with switchable graphics
pop-os/nvidia-graphics-drivers#122 (comment)
other programs would simply run with degraded performance

note that this does not tend to affect Vulkan apps (including anything running under DXVK) because it can directly request a more powerful dedicated GPU instead of relying on the default device.