Event for opening window

[lk-code]

implement event if webview2 wants to open a new window:

await this.MonacoEditorWebView.EnsureCoreWebView2Async();
if (this.MonacoEditorWebView.CoreWebView2 is not null)
{
    this.MonacoEditorWebView.CoreWebView2.NewWindowRequested += CoreWebView2_NewWindowRequested;
}