fix: Set authenticated: true after successful authentication

[KidkArolis]

Summary

Fixes #1360

[daffl]

Good call. I removed it because it seemed redundant but with #1317 bringing back the param it makes sense to set it.

[KidkArolis]

One alternative thought..

When i first wrote some feathers tests, it seemed a little superfluous that i had to pass both { user, authenticated }.

And so i think it was interesting that you were trying to remove the need for that param, by hiding it more behind an internal symbol.

But what if presence of user object would be enough to treat requests as authenticated. So instead of using/checking authenticated we just have { user }.