ui: transient errors like connection issues should not be persistent in the notifications dropdown

[buck54321]

When we have transient connection issues or a user has a flappy connection for a short time, it makes entries in the notifications dropdown that can be quite spammy. I think there a couple of things that need to happen. 1) Some notifications need a way to either be replaced by later notifications or merged together with similar unacked notifications, and 2) connection issues should maybe not always be sent as error notifications, but rather shown as UI elements and e.g. disabled forms.