Use label and Details button, check if connected

Keep "Use SASL Authentication" static, to avoid confusion and
concerns with longer languages.

Add another row with an icon, text, and "Details..." button to show
current SASL availability.

Check if disconnected separately from network existing and capability
negotiation support.  Show a different message when disconnected from
the network.  This should help reduce confusion.

Move SASL status UI updates to separate function to avoid cluttering
general capability updates handling function.