Fix DirectX install check + add Windows ARM64 build script + update CI

[yungcomputerchair]

Three things in the order that I did them:

• Add a build script for win-arm64
• Add the win-arm64 build flavor to the build matrix for the all-build job
• Fix where Dx9 helper looks for D3D9 DLLs
  • When I was testing, the launcher initially wouldn't let me launch, saying I was missing D3D9 even though I had it installed. This is because there is no native 64-bit DirectX on ARM, only 32-bit.
    • This actually brought up an existing bug, though. 32-bit DLLs live in SysWOW64, not System32. The game's System32 load is redirected to SysWOW64 on 64-bit machines (and this launcher is exclusively 64-bit).
    • So we should always be looking in SysWOW64 to ensure 32-bit DirectX is installed. The one in System32 is 64-bit. Very confusing. Thanks, Windows.
  • While I was in there, I noticed that for Linux and Mac, we also check for the DirectX DLLs under the Wine prefix, but this isn't necessary (or correct).
    • Wine intercepts calls to DirectX to its internal wined3d library. It doesn't actually use native DirectX DLLs, making this check actively harmful. Got rid of it; if Wine is installed on these platforms, it'll support DirectX without any DLLs needed.

[yungcomputerchair]

Buddy-tested on Windows x64, Windows ARM64, and Linux x64. No issues. Merging so we can release.