Testing #105764

When hosting the WebviewView in a "Panel" we should be able to "show" it via API, in my example below:

1. User clicks an item in a custom TreeDataProvider.
2. I update the content and title of the WebviewView (title does not update see: [WebviewView] Changing Title When webviewView.visible === false #106083)
3. I would like to force "show" the WebviewView panel.

For comparison the vscode.Terminal has show and hide methods.