[tests] Disable linking on Mono.Android.NET-Tests.csproj

Context: #6072
Context: dotnet/runtime#55375
Context: https://discord.com/channels/732297728826277939/732297837953679412/862829757460512788

@vargaz wondered if dotnet/runtime#55375 is because of the linker.

Disable the linker, and lets see what happens!

Author: jonpryor

tests/Mono.Android-Tests/Runtime-Microsoft.Android.Sdk/Mono.Android.NET-Tests.csproj

@@ -21,6 +21,8 @@
     <PlotDataLabelSuffix>-$(TestsFlavor)NET6</PlotDataLabelSuffix>
     <!-- TODO: Fix excluded tests -->
     <ExcludeCategories>DotNetIgnore</ExcludeCategories>
+    <!-- TESTING for xamarin/xamarin-android#6072 -->
+    <AndroidLinkMode>None</AndroidLinkMode>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">