People menu not showing up in activity sidebar when sidebar is already open

[wiswedel]

Describe the bug
Clicking on a name in the Activity sidebar tab doesn't have any effect.

To Reproduce
Steps to reproduce the behavior:

1. Browse to a file that has some activity by other persons (e.g. an office- or .md file)
2. Open the sidebar, open the Activity tab
3. Click on a person's name => people menu shows up (send email, talk to them...)
4. Open that file in the viewer
5. Click on a person's name in the Sidebar's Activity tab

Expected behavior
People menu shows up (send email, talk to them...)

Actual behavior
Nothing happens. Mouse transforms to pointer on hover, but click doesn't do anything.

Side note
This only happens when the sidebar is already open when the viewer opens.
Closing and re-opening the sidebar (or having it closed and only opening when the viewer is already loaded) leads to the expected behavior.

Tested on Nextcloud 20.0.1 and 19.0.2

[skjnldsv]

Will be fixed once this is migrated to our components I guess.
See nextcloud/server#20020