Updated to OnTopic Library preview

This preview release of the **OnTopic Library** includes new features such as the `GetByUniqueKey()` extension that can be used to replace helper functions in `TopicExtensions` (930538e).

Obviously, this will need to be updated to the release version once it's available—and prior to this update to the **OnTopic Data Transfer** library being released.

Author: JeremyCaney

OnTopic.Data.Transfer.Tests/OnTopic.Data.Transfer.Tests.csproj

@@ -14,7 +14,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="OnTopic" Version="4.1.0" />
+    <PackageReference Include="OnTopic" Version="4.3.0-empty-repository-support.52" />
   </ItemGroup>
 
   <ItemGroup>

OnTopic.Data.Transfer/OnTopic.Data.Transfer.csproj

@@ -36,7 +36,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="OnTopic" Version="4.1.0" />
+    <PackageReference Include="OnTopic" Version="4.3.0-empty-repository-support.52" />
     <PackageReference Include="System.ObjectModel" Version="4.3.0" />
     <PackageReference Include="System.Text.Json" Version="4.6.0" />
   </ItemGroup>