build(deps): update Splat requirement from 9.* to 10.* in /src (#2653)

Updates the requirements on [Splat](https://github.com/reactiveui/splat) to permit the latest version.
- [Release notes](https://github.com/reactiveui/splat/releases)
- [Changelog](https://github.com/reactiveui/splat/blob/main/RELEASENOTES.md)
- [Commits](reactiveui/splat@9.0.4...10.0.1)

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

src/ReactiveUI/ReactiveUI.csproj

@@ -22,7 +22,7 @@
   <ItemGroup>
     <Compile Remove="Platforms\**\*.cs" />
     <None Include="Platforms\**\*.cs" />
-    <PackageReference Include="Splat" Version="9.*" />
+    <PackageReference Include="Splat" Version="10.*" />
     <PackageReference Include="DynamicData" Version="7.*" />
     <PackageReference Include="System.Reactive" Version="5.0.0" />
   </ItemGroup>