deps(test): update dependency microsoft.net.test.sdk to 18.8.1 (#1198)

This PR contains the following updates:

| Package | Change |
[Age](https://docs.renovatebot.com/merge-confidence/) |
[Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
| [Microsoft.NET.Test.Sdk](https://redirect.github.com/microsoft/vstest)
| `18.7.0` → `18.8.1` |
![age](https://developer.mend.io/api/mc/badges/age/nuget/Microsoft.NET.Test.Sdk/18.8.1?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/nuget/Microsoft.NET.Test.Sdk/18.7.0/18.8.1?slim=true)
|

---

### Release Notes

<details>
<summary>microsoft/vstest (Microsoft.NET.Test.Sdk)</summary>

###
[`v18.8.1`](https://redirect.github.com/microsoft/vstest/releases/tag/v18.8.1)

#### What's Changed

- Fix protocol negotiation timeout when STJ reflection is disabled
(18.8.1) by [@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;16281](https://redirect.github.com/microsoft/vstest/pull/16281)

**Full Changelog**:
<microsoft/vstest@v18.8.0...v18.8.1>

###
[`v18.8.0`](https://redirect.github.com/microsoft/vstest/releases/tag/v18.8.0)

#### What's Changed

- Migrate from Newtonsoft.Json to System.Text.Json / Jsonite (merge to
main) by [@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;15687](https://redirect.github.com/microsoft/vstest/pull/15687)
- For more detail refer to
<https://devblogs.microsoft.com/dotnet/vs-test-is-removing-its-newtonsoft-json-dependency/>
- Create source-only filter package by
[@&#8203;Youssef1313](https://redirect.github.com/Youssef1313) in
[#&#8203;15638](https://redirect.github.com/microsoft/vstest/pull/15638)
  - Package release is pending.
- Add ARM64 msdia140.dll support to test platform packages by
[@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;15692](https://redirect.github.com/microsoft/vstest/pull/15692)
- Fix mutex cleanup crash on macOS/Linux by
[@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;15684](https://redirect.github.com/microsoft/vstest/pull/15684)
- Restrict artifact temp directory permissions on Unix by
[@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;15729](https://redirect.github.com/microsoft/vstest/pull/15729)
- Add support for filtering uncategorized tests with TestCategory=None
by [@&#8203;Evangelink](https://redirect.github.com/Evangelink) in
[#&#8203;15727](https://redirect.github.com/microsoft/vstest/pull/15727)
- Fix SCI binding failure in DTA hosts (main) by
[@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;15724](https://redirect.github.com/microsoft/vstest/pull/15724)
- Fix HTML logger parallel file collision by
[@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;15435](https://redirect.github.com/microsoft/vstest/pull/15435)
- Improve error message when testhost cannot be found by
[@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;16053](https://redirect.github.com/microsoft/vstest/pull/16053)
- Fix HTML logger exception on invalid XML chars in test display names
by [@&#8203;nohwnd](https://redirect.github.com/nohwnd) in
[#&#8203;16051](https://redirect.github.com/microsoft/vstest/pull/16051)

**Full Changelog**:
<microsoft/vstest@v18.7.0...v18.8.0>

</details>

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test/Directory.Build.props

@@ -10,7 +10,7 @@
 
     <ItemGroup>
         <PackageReference Include="FluentAssertions" Version="8.10.0" />
-        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.8.1" />
         <PackageReference Include="xunit.v3" Version="3.2.2" />
         <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>