batch-open-conversations: missing checkboxes #3486

Summary

• Checkboxes missing for batch-open-conversations

Where

• when i go to Issues or Pull Requests (or bugs), for example https://github.com/sindresorhus/refined-github/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc

What i see

• missing checkboxes (note: the Open all checkbox is visible)

  <img width="710" alt="Missing Checkboxes" src="https://user-images.githubusercontent.com/184316/90654025-37ca2380-e240-11ea-902d-a122ba000b1b.png">

What i Expect

• see checkboxes like this image:

Environment

Chrome: Version 84.0.4147.135 (Offizieller Build) (64-Bit) Refined GitHub: 20.8.16