Bump NUnit from 4.2.2 to 4.3.0 in /samples (#351)

Author: dependabot[bot]

src/CommunityToolkit.Maui.Markup.UnitTests/CommunityToolkit.Maui.Markup.UnitTests.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="NUnit" Version="4.2.2" />
+    <PackageReference Include="NUnit" Version="4.3.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" PrivateAssets="all" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="coverlet.collector" Version="6.0.2" PrivateAssets="all" />