Bump the dotnet group with 2 updates (#54041)

Bumps Microsoft.NET.Test.Sdk from 18.5.1 to 18.6.0
Bumps NUnit from 4.6.0 to 4.6.1

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: dotnet
- dependency-name: NUnit
  dependency-version: 4.6.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dotnet
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

samples/snippets/core/testing/unit-testing-using-nunit/csharp/PrimeService.Tests/PrimeService.Tests.csproj

@@ -9,9 +9,9 @@
 
   <!--<snippetPackages>-->
   <ItemGroup>
-    <PackageReference Include="nunit" Version="4.6.0" />
+    <PackageReference Include="nunit" Version="4.6.1" />
     <PackageReference Include="NUnit3TestAdapter" Version="6.2.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
     <PackageReference Include="NUnit.Analyzers" Version="4.13.0">
         <PrivateAssets>all</PrivateAssets>
         <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>