Window preview is cut to Windowed mode resolution in Borderless/Fullscreen mode

**Describe the bug:** Works correctly with --tk flag
Window preview always cuts to the size of the window in Windowed mode, when it should show the full window in Fullscreen or Borderless modes

**Screenshots or videos showing encountered issue:** https://streamable.com/171yp4

**osu!lazer version:** 2020.1204.0

**Logs:**
[runtime.log](https://github.com/ppy/osu/files/5647420/runtime.log)

