numpy_interface/algorithms: use `== 1` instead of `is 1`
Seen here: https://gitlab.kitware.com/paraview/paraview-superbuild/-/jobs/5347097#L132
Backport: paraview/release
Seen here: https://gitlab.kitware.com/paraview/paraview-superbuild/-/jobs/5347097#L132
Backport: paraview/release