[workload] use **FromWorkload** for targeting/runtime pack versions (#2122)

Context: dotnet/sdk#19596

If we use the version number string of `**FromWorkload**`, then our
runtime packages don't need to be resolved from a NuGet feed. They can
be resolved from the `dotnet/packs` directory.

This completely eliminates the need for a `NuGet.config` file for
projects when you have the `maui` workload installed.

One caveat for dotnet/maui is we have a `$(MicrosoftMauiSdkVersion)`.
We'll need to use `**FromWorkload**` in some places, and the actual
number when declaring `@(PackageReference)`.

Author: jonathanpeppers

samples/Directory.Build.props

@@ -4,13 +4,5 @@
     <UseMaui Condition=" '$(UseWorkload)' == 'true' ">true</UseMaui>
   </PropertyGroup>
   <Import Project="../../../Directory.Build.props" />
-  <!--
-    We don't want to use cached Microsoft.Maui.* runtime packs.
-    This can be removed when we get: https://github.com/dotnet/sdk/issues/14044
-  -->
-  <PropertyGroup Condition=" '$(UseMaui)' == 'true' ">
-    <RestoreNoCache>true</RestoreNoCache>
-    <RestorePackagesPath>$(MauiRootDirectory)packages/</RestorePackagesPath>
-  </PropertyGroup>
   <Import Project="Maui.InTree.props" Condition=" '$(UseMaui)' != 'true' " />
 </Project>