Temporarily mitigate loss of docs.scipy.org from blocking pipelines.lsst.io and developer.lsst.io builds

Mitigate the temporary loss of docs.scipy.org as an intersphinx target in pipelines.lsst.io and developer.lsst.io builds. Solution is to remove the -W flag to prevent warnings from becoming errors that block merges.

See also: https://community.lsst.org/t/how-docs-scipy-org-and-intersphinx-affect-your-doc-builds/1717?u=jsick