* Use `has_too_many_connection_errors` to avoid showing the banner immediately
* Increase toast duration to avoid frequent, distracting flashing of the toast
* Automatically dismiss the toast when the connection comes back up
* Include `close_button` for user to dismiss the toast
* If the user dismisses the toast, do not show it again until the connection comes back and drops again
* Use `connection_error` var instead of a custom util_hook to get the message

* Hide the connection pulser behind the toast (33x33)
* Add a title (tooltip) that shows the connection error

If the user dismisses the toast, we still want to indicate that the backend is
actually down.

…r_connection_error