Enable bundling NativeAOT NuGet packages from runtime on non-vmr builds.

The NativeAOT bundeling added in https://github.com/dotnet/sdk/pull/41198 is copying NuGet packages directly from the `runtime` repo build output:

https://github.com/dotnet/sdk/blob/01aab3448c9185f2a5b7e66e7e327fe4b7841408/src/Installer/redist-installer/targets/GenerateLayout.targets#L212-L214

This location is not available when the SDK is built outside of the vmr.

This issue is for replacing that copy with obtaining the packages through a NuGet source. See https://github.com/dotnet/sdk/pull/41198#discussion_r1644430402.

When this is working the, the `DotNetBuildOrchestrator` condition can be removed here:

https://github.com/dotnet/sdk/blob/01aab3448c9185f2a5b7e66e7e327fe4b7841408/src/Installer/redist-installer/redist-installer.csproj#L11-L12

cc @ViktorHofer

Start with src/Installer/redist-installer/targets/GenerateLayout.targets at the linked lines and the DotNetBuildOrchestrator condition in src/Installer/redist-installer/redist-installer.csproj. Read the discussion on dotnet/sdk#41198 to understand the intended NuGet source, then verify that non-vmr SDK builds bundle the NativeAOT packages and that the condition can be removed.

Written by the indexing model from the issue text.