Update Backend.Test dependencies (#4076)

* Bump the backend-deps group with 2 updates

Bumps Microsoft.NET.Test.Sdk from 18.0.0 to 18.0.1
Bumps NUnit3TestAdapter from 5.2.0 to 6.0.1

* Remove Microsoft.Extensions.Caching.Memory ref (automatically included in a net8.0 Sdk.Web project)

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Danny Rorabaugh <imnasnainaec@gmail.com>

Author: dependabot[bot]

Backend.Tests/Backend.Tests.csproj

@@ -12,11 +12,10 @@
     <NoWarn>$(NoWarn);CA1305;CA1859;CS1591</NoWarn>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="9.0.10" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
     <PackageReference Include="Moq.Contrib.HttpClient" Version="1.4.0" />
     <PackageReference Include="NUnit" Version="4.4.0" />
-    <PackageReference Include="NUnit3TestAdapter" Version="5.2.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="6.0.1" />
     <PackageReference Include="coverlet.collector" Version="6.0.4"/>
     <PackageReference Include="coverlet.msbuild" Version="6.0.4"/>
   </ItemGroup>