Using .file kind and .downloading file operation kind will produce a more appropriate localizedAdditionalDescription.
The fileTotalCount and fileCompletedCount aren't appropriate for this case, because there's only one file being downloaded.
This reverts the change from 90c067997b so that the username is shown in situations where we don't have a valid session but could almost certainly get one. Instead, to achieve what that commit was trying to do, we'll instead remove the username from UserDefaults if auth fails with an invalid username or password error. I think this will more closely match what users expect in this UI.
I've added a comment in the UI explaining why it is the way it is. It might also be worth considering renaming AuthenticationState or its cases to better reflect that it's probably more about the (short-lived) session state than whether the user has signed in before and has stored their credentials.
We were appending a version without appending a corresponding AvailableXcode, and these two arrays were being zipped later so they wouldn't line up. This change simplifies this method a bit by working on only a single array, and then also moves that appending to the end after the array of Xcodes is created.
I removed this because I thought it wasn't necessary for some reason. We do send a SIGTERM if the user cancels the installation (via subscription cancellation), but if the whole app quits aria2c would keep running in the background.
The previous implementation was doing something weird when it was used during installation in:
verifySecurityAssessment(of: installedXcode)
.combineLatest(self.verifySigningCertificate(of: installedXcode.path.url))
It looks like it would subscribe after the Process.run future had already sent a value, and so it would never finish. This seems weird, and I'm assuming that I'm misunderstanding something about this behaviour, but dispatching manually seems reasonable and works.
