fix(CI): update workflow for uploading binaries to artifactory (#4746)

Update the nix CI runner. This commit does not modify any source code
files. The unix builds were successful, but the binaries were not
uploaded to the internal artifactory. This PR borrows an idea from
@ximinez to attempt to fix this issue.

After successful authentication, the `outcome` variable contains a
string. In the upload step, we are checking if outcome == 'success' as a
prerequisite for uploading the binary.

This commit updates the contents of the `outcome` variable.

.github/workflows/nix.yml

@@ -79,7 +79,7 @@ jobs:
       - name: try to authenticate to ripple Conan remote
         id: remote
         run: |
-          echo outcome=$(conan user --remote ripple ${{ secrets.CONAN_USERNAME }} --password ${{ secrets.CONAN_TOKEN }} && echo success || echo failure) | tee ${GITHUB_OUTPUT}
+          echo outcome=$(conan user --remote ripple ${{ secrets.CONAN_USERNAME }} --password ${{ secrets.CONAN_TOKEN }} >&2 && echo success || echo failure) | tee ${GITHUB_OUTPUT}
       - name: archive profile
         # Create this archive before dependencies are added to the local cache.
         run: tar -czf conan.tar -C ~/.conan .