handle initial state

[feloy]

With #178, we introduce a delay before the first event is sent from the extension to the webview.

The webview states rely on these events, so these states have initial "empty" values during this delay.

The components for the moment are using a timer to wait for this delay before to display the screens equivalent of the "empty" values. Typically, the no contexts screens: https://github.com/podman-desktop/extension-kubernetes-dashboard/blob/v0.1.0/packages/webview/src/component/objects/KubernetesObjectsList.svelte#L143

We need to find a way to detect when the states are in their initial "empty" value, or have received their first value from extension's events.