Consider whether to add `company_owned_by_local_gov` to `poisoned` bodies

[WilliamWDTK]

If we don't, then this will allow a tag-based note explaining why we list bodies (if we decide it's necessary).

There are currently two bodies tagged with both:

• https://www.whatdotheyknow.com/body/goosepool_2019_limited
• https://www.whatdotheyknow.com/body/warrington_borough_transport