Prevent Microsoft.AspNetCore.App.Internal.Assets from being restored when not needed

[mthalman]

When running dotnet publish with self-contained deployment on a plain old web app, it causes the Microsoft.AspNetCore.App.Internal.Assets package to be restored from nuget.org even though that package isn't actually used by the deployed app it's not Blazor). This should be avoided because it's problematic when using a source built .NET SDK (see #46055 (comment)).

Repro steps:

1. Install a CentOS Stream 9 source built .NET 10 SDK
2. dotnet new webapp
3. dotnet publish --self-contained true -r centos.9-x64

This was found when attempting to enable the self-contained tests for the VMR: #46055

[ViktorHofer]

cc @javiercn @MackinnonBuck

[tmds]

Per @maraf's comment the package dependency is added based on UsingMicrosoftNETSdkRazor.

UsingMicrosoftNETSdkRazor is currently set on any ASP.NET Core project through the Microsoft.NET.Sdk.Web SDK.

Since this is a non source-buildable dependency which doesn't ship with a source-build SDK, we want to minimize the projects that depend on it.

cc @omajid

[MichaelSimons]

@javiercn, can you provide some guidance or refer to someone who can? TIA.