Improve UX and fix bugs regarding logging out of an Enterprise Server

CC #6913.

The correct way to prevent Enterprise server connection warnings and errors, if you do not want to be connected to the server, is to log out of the server. Enterprise has no way of knowing a priori whether you are totally offline or if there is a legitimate connection error. Trying to solve that problem with tons of heuristics is not something we're interested in doing or even sure if we can do successfully.

Unfortunately, after talking with @ElykDeer, it appears pretty trivial for a user away from their Enterprise server to be unable to log out of the server to prevent the errors, which I believe may be two separate bugs.

What Works

If you have a client that was, at some point, actively connected, you can:

1. Click on the Remote Browser
2. Click "Disconnect"
3. Click "Log Out"

This will properly log your client out and, after restarting, it won't show any of the errors.

What Doesn't Work

If you have already restarted your client while it was offline, and you click on the button to show the Remote Browser, you are greeted with this:

This is correct: You are not, currently, connected to an Enterprise server! But, you are still "logged into" one. This is the first 'bug': It's not obvious what's happening here, and it's not obvious to the user how to proceed. We need to find a better way to surface the "logged in" status to users, especially in this state.

If, here, you click "Connect...", you will see this dialog:

This dialog surfaces the ability for the user to "log out". But, if you click "log out" and restart the client, it will still show all the earlier error messages. So, clearly some part of the state for this is being kept around, and it should not. This is the second 'bug'.

What We Should Do

In the short-term, we should fix both of the bugs above. In the long-term, we should discuss how we can surface the status of being "logged into" an Enterprise server better for users. It might be that what we've implemented here could be implemented better, and theoretically we should also have the ability to log out of all Enterprise servers (in the event that someone is connected to multiple) as well with a single action.