Bump FluentAssertions from 5.10.3 to 6.6.0

Bumps [FluentAssertions](https://github.com/fluentassertions/fluentassertions) from 5.10.3 to 6.6.0.
- [Release notes](https://github.com/fluentassertions/fluentassertions/releases)
- [Changelog](https://github.com/fluentassertions/fluentassertions/blob/develop/AcceptApiChanges.ps1)
- [Commits](fluentassertions/fluentassertions@5.10.3...6.6.0)

---
updated-dependencies:
- dependency-name: FluentAssertions
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

test/Directory.Build.props

@@ -6,7 +6,7 @@
     <ItemGroup>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
         <PackageReference Include="Moq" Version="4.17.2" />
-        <PackageReference Include="FluentAssertions" Version="5.10.3" />
+        <PackageReference Include="FluentAssertions" Version="6.6.0" />
         <PackageReference Include="Bogus" Version="33.0.2" />
         <PackageReference Include="xunit" Version="2.4.1" />
         <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">