Update Caliburn.Micro.Maui.Tests to .NET 9

Co-authored-by: vb2ae <[email protected]>

Author: Copilot

src/Caliburn.Micro.Maui.Tests/Caliburn.Micro.Maui.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <UseMaui>true</UseMaui>
@@ -16,7 +16,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="Microsoft.Maui.Controls" Version="8.0.92" />
+    <PackageReference Include="Microsoft.Maui.Controls" Version="9.0.120" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
     <PackageReference Include="xunit" Version="2.9.2" />