Blazor WebAssembly Standalone authorization via AAD template does not (can not?) use authorization code flow (w/PKCE)...

[mattemoore]

Describe the bug

When creating a Blazor WASM Standalone SPA as described here: https://docs.microsoft.com/en-us/aspnet/core/blazor/security/webassembly/standalone-with-azure-active-directory?view=aspnetcore-3.1 , the application uses implicit grant flow as opposed to recommended and more secure authorization code flow.

To Reproduce

1. Register AD application in Azure portal with Authentication platform of type SPA with redirect URI of https://localhost:5001/authentication/login-callback
2. Ensure that implicit grant access tokens and id tokens are disabled.
3. Create Blazor WASM app via dotnet new blazorwasm -au SingleOrg --client-id "{CLIENT ID}" --tenant-id "{TENANT ID}"
4. Run app.
5. Click Login.

Exceptions (if any)

https://localhost:5001/authentication/login-failed?message=AADSTS700054:%20response_type%20%27id_token%27%20is%20not%20enabled%20for%20the%20application...
This exception is fixed when implicit flow is enabled but this is not the goal. The goal is to use the more secure authorization code flow.

Further technical details

 ~/Code/blazor_webassembly_AD_SPA  master +32 !1  dotnet --info                                                                                                          
.NET Core SDK (reflecting any global.json):
 Version:   3.1.301
 Commit:    7feb845744

Runtime Environment:
 OS Name:     pop
 OS Version:  20.04
 OS Platform: Linux
 RID:         linux-x64
 Base Path:   /usr/share/dotnet/sdk/3.1.301/

Host (useful for support):
  Version: 3.1.5
  Commit:  65cd789777

.NET Core SDKs installed:
  3.1.301 [/usr/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.App 3.1.5 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.5 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

[mkArtakMSFT]

Thanks for contacting us.
The support for this is not in GA yet. If this gets released in the coming month, we may consider bringing support for this in.

[mkArtakMSFT]

Thanks for contacting us.
We're moving this issue to the Next sprint planning milestone for future evaluation / consideration. We will evaluate the request when we will planning the work for the next milestone. To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[mkArtakMSFT]

This is going to be handled as part of #23821