chore(deps): update dependency fluentassertions to 8.9.0

Author: renovate[bot]

src/directory.packages.props

@@ -27,7 +27,7 @@
   <ItemGroup>
     <PackageVersion Include="coverlet.collector" Version="8.0.0" />
     <PackageVersion Include="coverlet.msbuild" Version="8.0.0" />
-    <PackageVersion Include="FluentAssertions" Version="8.8.0" />
+    <PackageVersion Include="FluentAssertions" Version="8.9.0" />
     <PackageVersion Include="FluentAssertions.Analyzers" Version="0.34.1" />
     <PackageVersion Include="ReactiveUI.Testing" Version="22.3.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />