[1.8.x] Refs #24625 -- Filtered docutils warnings output in tests

Instead of setting ``warning_stream`` in the docutils config overrides
to ``False`` I opted for filtering the stderr in the tests to keep the
error output showing up in server logs.

Thanks Tim Graham for the report and review

Backport of 3caf7efb44712f89d6552076c240a3c898673a2c from master

0 files changed, 0 insertions, 0 deletions