Skip DeathReaper tests when `pydiscourse` is not importable (#443)

Depending whether Poetry virtualenv contains pydiscourse, it will skip or not tests.unit.wot.exclusions

pydiscourse is installed when specifying poetry install --extras deathreaper

https://docs.pytest.org/en/7.1.x/how-to/skipping.html#skipping-on-a-missing-import-dependency

changed milestone to %0.12.0

added DeathReaper Dep Dev Env Test enhancement labels

requested review from @moul

assigned to @moul

approved this merge request

merged