Duplicated account appears in list of available accounts

### What is the issue?

When I used fast user switching to switch from account A to account B, subsequently switching back to account A shows there are now 2 account A's appearing in the list of available accounts.

### Steps to reproduce

Here's what I *believe* happened:

1. Used the Tailscale client to switch from user A to user B. I had not used user switching for a minimum of several weeks. Prior to this switch, only user A and user B appeared as options for user switching.
2. Switched back to user A.
3. Noticed sometime later that my list of accounts (viewable from the Tailscale client UI) shows 2 user A accounts and the B account.

### Are there any recent changes that introduced the issue?

Unknown

### OS

macOS

### OS version

Ventura 13.1

### Tailscale version

Version 1.39.73 (App Store)

### Other software

_No response_

### Bug report

UG-e39220bc8ff99bdaea0076aa90fa66ee8f50651b56942ec1b899f7ccd8ba62d7-20230329154650Z-5e2744e3eb8c20f6