Merged PR 3725: Bump Microsoft.NET.Test.Sdk from 16.9.1 to 16.9.4

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.9.1 to 16.9.4.

#Release notes

*Sourced from [Microsoft.NET.Test.Sdk's releases](https://github.com/microsoft/vstest/releases).*

> ## v16.9.4
> See the release notes [here](https://github.com/microsoft/vstest-docs/blob/master/docs/releases.md#1694).

#Commits

- [`99b911a`](microsoft/vstest@99b911a) Merging servicing fixes for 16.9.4 ([#2837](microsoft/vstest#2837))
- See full diff in [compare view](microsoft/vstest@v16.9.1...v16.9.4)

src/Falu.Tests/Falu.Tests.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.4" />
     <PackageReference Include="Moq" Version="4.16.1" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.analyzers" Version="0.10.0" />