Remove Octave-mex artifact upload step in build.yml

The step to upload Octave-mex artifacts has been removed from the
GitHub Actions workflow configuration file (build.yml). This step
was previously conditional, running only on Windows runners, and
used the actions/upload-artifact@v4 action to upload artifacts
from a specified path with a given name.

Author: ptahmose

.github/workflows/build.yml

@@ -145,7 +145,6 @@ jobs:
           echo "linuxx64_octave_build=${name}" >> $GITHUB_OUTPUT
       - name: Upload Octave-mex artifacts
         uses: actions/upload-artifact@v4
-        if: runner.os == 'Windows'  # currently we only build Octave mex files on Windows
         with:
           path: ${{ env.artifactPath }}/
           name: ${{ env.artifactName }}