Retry button (for transient failed server connections)

### Feature description

I'm running NC on a local server with Tailscale as the VPN. It takes a little bit for Tailscale to complete it's ability to connect.
When the NC desktop loads, it can't find the server and flags that as a failed connection. Unfortunatley there's no way to force that to refresh. A simple retry button on the warning would likely be all I need.

No files, tests, or entry points are named. Start by locating the desktop client's failed-server connection warning and the connection flow it uses; done means a user can retry after a transient failure and receive an updated connection result.

Written by the indexing model from the issue text.