Qt: fix game window position on multi monitor setups

[Megamouse]

• fix game window position on multi monitor setups.
  fixes Dual screen woes with DPI mismatch as seasoning #10027

[dio-gh]

Fixes positioning and size shenanigans on and from the secondary screen, but on the primary screen with 1.25x scaling the game window is now scaled by 1.25x also. Is that expected behaviour? Thought the expected behaviour is to not scale unless you can scale by an integer.

[Megamouse]

We don't scale anything.
If your screen is set to 125% then obviously all apps that support hidpi will be automatically scaled.
So it's expected.

[Megamouse]

If you don't want that you need to disable it or change the rounding policy

[dio-gh]

After testing a previous build I can at least confirm it's not a new change, so the PR is mergeable. It's not that I don't want or want something, I just didn't expect that we allow Windows to do non-integer scaling on the graphics output.

[Boii1]

I have tested this build in Little Big Planet and it tanks the performances from 30FPS to 20-25FPS. Can't hit 30 FPS anymore. The previous update works perfectly fine and hits 30FPS with zero drops.

Specs:
5950X
RTX 3080
2x16GB DDR4 16 18 18 38
ROG Crosshair VIII Dark Hero

[elad335]

@Boii1 Closed pull request is a bad place to report problems, open an issue instead.