Improve discoverability of the account menu

I figure that not many users know there's a secret and super useful account menu. Right-clicking or long-pressing opens this menu. Additionally, tapping your avatar brings up the "Accounts" settings for some reason. Worse, there's no indication of any of this functionality or why we're hiding two separate functions here.

Instead, let's make it a ToolButton but keep the general appearance the same. That makes it act and feel more like a regular button, and pressing on it will open the account menu. The shortcut to the accounts settings is removed, there's plenty of other ways to get there.