FreeBSD: VID-3d19c776-68e7-11ea-91db-0050562a4d7b: www/py-bleach -- multiple vulnerabilities

* ``bleach.clean`` behavior parsing embedded MathML and SVG content with RCDATA tags did not match browser behavior and could result in a mutation XSS. Calls to ``bleach.clean`` with ``strip=False`` and ``math`` or ``svg`` tags and one or more of the RCDATA tags ``script``, ``noscript``, ``style``, ``noframes``, ``iframe``, ``noembed``, or ``xmp`` in the allowed tags whitelist were vulnerable to a mutation XSS. * ``bleach.clean`` behavior parsing ``noscript`` tags did not match browser behavior. Calls to ``bleach.clean`` allowing ``noscript`` and one or more of the raw text tags (``title``, ``textarea``, ``script``, ``style``, ``noembed``, ``noframes``, ``iframe``, and ``xmp``) were vulnerable to a mutation XSS.