Add a health check to confirm that rosetta was installed

[srid]

Some projects explicitly use x86_64-darwin packages even on ARM macs:

https://github.com/nammayatri/nammayatri/blob/ad935fb58e8dd909a311777b39792c1a40fade01/Backend/nix/services/nammayatri.nix#L292-L296

Without installing rosetta, the dev would see:

For this, we need to add a check to verify that Nix can build packages for x86_64-darwin.

It might be worth doing this in a more general fashion, by calling the health check canBuildFor. So nammayatri flake can contain:

{ 
  nix-health.default = {
    can-build-for.systems."aarch64-darwin" = [ "x86_64-darwin" ];
  };
}

Or, if that's an overkill, we can just check that rosetta was installed, which would then look like:

{
  nix-health.default = {
    rosetta = {
      installed = true;
    };
  };
}

https://apple.stackexchange.com/a/464165/5007