Switch back to FluentAssertions 7.0

Directory.Packages.props

@@ -9,7 +9,7 @@
     <PackageVersion Include="DataGridExtensions" Version="2.6.0" />
     <PackageVersion Include="DiffLib" Version="2025.0.0" />
     <PackageVersion Include="Dirkster.AvalonDock.Themes.VS2013" Version="4.72.1" />
-    <PackageVersion Include="FluentAssertions" Version="8.0.0" />
+    <PackageVersion Include="FluentAssertions" Version="7.0.0" />
     <PackageVersion Include="ILCompiler.Reflection.ReadyToRun.Experimental" Version="9.0.1-rtm.24557.9" />
     <PackageVersion Include="Iced" Version="1.21.0" />
     <PackageVersion Include="JunitXml.TestLogger" Version="5.0.0" />