[Blazor] Add default IILink.Descriptors.xml to Components.WebAssembly

[javiercn]

This is meant to help avoiding accidental trimming on some common framework types used during serialization in JS interop.

<ItemGroup>
  <EmbeddedResource Include="ILLink.Descriptors.xml">
    <LogicalName>ILLink.Descriptors.xml</LogicalName>
  </EmbeddedResource>
</ItemGroup>

<linker>
  <assembly fullname="System.Runtime">
    <type fullname="System.Collections.Generic.KeyValuePair`2" preserve="all" />
  </assembly>
</linker>

[MihuBot]

Possible related and/or duplicate issue:

• A published blazor wasm app throws a serialization error "Unhandled exception rendering component: ConstructorContainsNullParameterNames" #52947