Active File Context is not updating reliably when files become file-based apps

This has been observed when adding `#:` directives when files didn't previously contain them.

The behavior is that the label stays stuck as "Miscellaneous file" and only changes to "appname (net10.0)" for example, after you close/reopen the tab.

https://github.com/dotnet/vscode-csharp/blob/6743a5a153b9d9013dba063afc4def03b93c9f51/src/lsptoolshost/projectContext/projectContextService.ts#L25

@JoeRobich do you have any suggestions on how to start investigating this? I think that the server may be failing to send some notification once the file is loaded as a file-based program.