MINOR: [C#] Bump xunit.skippablefact from 1.4.13 to 1.5.23 in /csharp

Bumps [xunit.skippablefact](https://github.com/AArnott/Xunit.SkippableFact) from 1.4.13 to 1.5.23.
- [Release notes](https://github.com/AArnott/Xunit.SkippableFact/releases)
- [Commits](AArnott/Xunit.SkippableFact@v1.4.13...v1.5.23)

---
updated-dependencies:
- dependency-name: xunit.skippablefact
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

csharp/test/Apache.Arrow.Tests/Apache.Arrow.Tests.csproj

@@ -22,7 +22,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="xunit.skippablefact" Version="1.4.13" />
+    <PackageReference Include="xunit.skippablefact" Version="1.5.23" />
     <PackageReference Include="pythonnet" Version="3.0.4" />
   </ItemGroup>