ggml-metal.metal MUST be copied to output folder

Metal depends on this file to execute, and MacOS llama.cpp defaults is now METAL.

LLama/LLamaSharp.Runtime.targets

@@ -32,7 +32,7 @@
             <Link>libllama.dylib</Link>
         </None>
         <None Include="$(MSBuildThisFileDirectory)runtimes/ggml-metal.metal">
-            <CopyToOutputDirectory>None</CopyToOutputDirectory>
+            <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
             <Link>ggml-metal.metal</Link>
         </None>    
     </ItemGroup>