Audit and fix Blazor's PWA manifest

[captainsafia]

Using this to track auditing and updating Blazor's web manifest per the criteria outlined in https://web.dev/install-criteria/.

• short_name or name
• icons - must include a 192px and a 512px icon
• start_url
• display - must be one of fullscreen, standalone, or minimal-ui
• prefer_related_applications must not be present, or be false

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.