Update samples to use latest net9.0 release and CTD release.

[adrianhall]

Work:

• Update to AspNetCore 9.0.4 and EF Core 9.0.4
• Update all other packages as well
• Update to CommunityToolkit.Datasync.* v9.0.2

[adrianhall]

Branch: issues/341

• datasync-server
• datasync-server-cosmosdb
• todoapp (all variants)
• todoapp-mvc
• todoapp-tutorial

Note: todoapp-tutorial does not compile - needs investigation.