Bump the dotnet group across 1 directory with 4 updates

Bumps the dotnet group with 4 updates in the /docs/azure/sdk/snippets/unit-testing directory: [coverlet.collector](https://github.com/coverlet-coverage/coverlet), [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest), [NSubstitute](https://github.com/nsubstitute/NSubstitute) and [xunit.runner.visualstudio](https://github.com/xunit/visualstudio.xunit).


Updates `coverlet.collector` from 6.0.2 to 6.0.3
- [Release notes](https://github.com/coverlet-coverage/coverlet/releases)
- [Commits](coverlet-coverage/coverlet@v6.0.2...v6.0.3)

Updates `Microsoft.NET.Test.Sdk` from 17.11.1 to 17.12.0
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Changelog](https://github.com/microsoft/vstest/blob/main/docs/releases.md)
- [Commits](microsoft/vstest@v17.11.1...v17.12.0)

Updates `NSubstitute` from 5.1.0 to 5.3.0
- [Release notes](https://github.com/nsubstitute/NSubstitute/releases)
- [Changelog](https://github.com/nsubstitute/NSubstitute/blob/main/CHANGELOG.md)
- [Commits](nsubstitute/NSubstitute@v5.1.0...v5.3.0)

Updates `xunit.runner.visualstudio` from 2.8.2 to 3.0.0
- [Release notes](https://github.com/xunit/visualstudio.xunit/releases)
- [Commits](xunit/visualstudio.xunit@2.8.2...3.0.0)

---
updated-dependencies:
- dependency-name: coverlet.collector
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dotnet
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: dotnet
- dependency-name: NSubstitute
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: dotnet
- dependency-name: xunit.runner.visualstudio
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: dotnet
...

Signed-off-by: dependabot[bot] <support@github.com>

docs/azure/sdk/snippets/unit-testing/UnitTestingSampleApp.csproj

@@ -12,15 +12,15 @@
   <ItemGroup>
     <PackageReference Include="Azure.Core" Version="1.44.1" />
     <PackageReference Include="Azure.Security.KeyVault.Secrets" Version="4.7.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="Moq" Version="[4.20.72]" /> <!-- Context: https://github.com/Azure/azure-sdk-for-net/issues/38111 -->
-    <PackageReference Include="NSubstitute" Version="5.1.0" />
+    <PackageReference Include="NSubstitute" Version="5.3.0" />
     <PackageReference Include="xunit" Version="2.9.2" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.0.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.collector" Version="6.0.2">
+    <PackageReference Include="coverlet.collector" Version="6.0.3">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>