build(deps): update Splat requirement from 13.* to 14.* in /src (#3057)

Updates the requirements on [Splat](https://github.com/reactiveui/splat) to permit the latest version.
- [Release notes](https://github.com/reactiveui/splat/releases)
- [Commits](reactiveui/splat@13.1.1...14.1.1)

---
updated-dependencies:
- dependency-name: Splat
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/ReactiveUI/ReactiveUI.csproj

@@ -113,7 +113,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Splat" Version="13.*" />
+    <PackageReference Include="Splat" Version="14.*" />
     <PackageReference Include="DynamicData" Version="7.*" />
   </ItemGroup>