Users can hide their public profile and presence information by checking
“Hide my public profile and presence features” on the
`u/{username}/preferences/interface` page. In that case, we also don't
want to return user status from the server.
This work has been started in https://github.com/discourse/discourse/pull/23946.
The current PR fixes all the remaining places in Core.
Note that the actual fix is quite simple – a5802f484d.
But we had a fair amount of duplication in the code responsible for
the user status serialization, so I had to dry that up first. The refactoring
as well as adding some additional tests is the main part of this PR.
We call the `/u/search/users` URL when autocompleting users. It returns
user's name, username and avatar template, but not user ID.
We need it to return user IDs in order to display user status in certain situations.
I could add ID to FoundUserWithStatusSerializer, so it will be added only if
user status is enabled in site settings. But I feel that it's good to always return it,
it's not a lot of data comparing to what we already return, and it should be useful
in other scenarios.
