docker(install): use undock to extract image

[crazy-max]

follow-up #438 (review)

[crazy-max]

Hum on macOS, buildx is not available so we can't use the imagetools command to get the image config for lima: https://github.com/docker/actions-toolkit/actions/runs/12857983316/job/35846515916?pr=567#step:10:51

FAIL __tests__/docker/install.test.itg.ts (20.152 s)
  ● Console

    console.error
      Error: Unable to locate executable file: buildx. Please verify either the file path exists or the file can be found within a directory specified by the PATH environment variable. Also check the file mode to verify the file is executable.
          at Object.<anonymous> (/Users/runner/work/actions-toolkit/actions-toolkit/node_modules/@actions/io/src/io.ts:170:15)
          at Generator.next (<anonymous>)
          at fulfilled (/Users/runner/work/actions-toolkit/actions-toolkit/node_modules/@actions/io/lib/io.js:24:58)

moby/moby#49301 could solve this issue so we don't require buildx.