chore(deps): update dependency microsoft.net.test.sdk to 18.9.0

Author: renovate[bot]

Jellyfin.Plugin.Themerr.Tests/Jellyfin.Plugin.Themerr.Tests.csproj

@@ -18,7 +18,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="JunitXml.TestLogger" Version="8.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.8.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.9.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">