chore(deps): update dependency microsoft.net.test.sdk to v18 (#285)

| datasource | package                | from    | to     |
| ---------- | ---------------------- | ------- | ------ |
| nuget      | Microsoft.NET.Test.Sdk | 17.14.1 | 18.0.0 |

Signed-off-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>
Co-authored-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>

Author: renovate-sh-app[bot]

tests/Grafana.OpenTelemetry.Tests/Grafana.OpenTelemetry.Tests.csproj

@@ -11,7 +11,7 @@
   <ItemGroup>
     <PackageReference Include="coverlet.collector" Version="6.0.4" />
     <PackageReference Include="GitHubActionsTestLogger" Version="2.4.1" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" />
   </ItemGroup>