BUG: Windows build fails on invalid CSC_LINK file when custom sign exe is provided

[rathboma]

Given this windows configuration:

  win: {
    icon: './public/icons/png/512x512.png',
    target: ['nsis', 'portable'],
    publish: ['github'],
    sign: "./build/win/sign.js",
  },

and a CSC_LINK for MacOS of: ~/mac-certificate.p12, the build will fail with ⨯ Env WIN_CSC_LINK is not correct, cannot resolve: C:\Users\runneradmin\mac-certificate.p12 doesn't exist

Even though signing will take place using sign.js.

Example of this occuring:
https://github.com/beekeeper-studio/beekeeper-studio/actions/runs/12224806820/job/34099608086#step:23:132