Fix attribute property injection timing issue

Test attributes like MyDataProvider were being initialized before their
properties were injected, causing 'Expected InnerClass to not be null'
errors in dependency injection scenarios.

Added property injection for test attributes before initialization to
ensure data source generators have their dependencies ready.

Co-authored-by: Tom Longhurst <thomhurst@users.noreply.github.com>

Author: claude[bot]

TUnit.Engine/Services/SingleTestExecutor.cs

@@ -138,6 +138,14 @@ await PropertyInjectionService.InjectPropertiesAsync(
             // Note: Property-injected values are already tracked within PropertyInjectionService
             // No need to track them again here
 
+            // Inject properties into test attributes before they are initialized
+            // This ensures that data source generators and other attributes have their dependencies ready
+            await PropertyInjectionService.InjectPropertiesIntoArgumentsAsync(
+                test.Context.TestDetails.Attributes.ToArray(), 
+                test.Context.ObjectBag, 
+                test.Context.TestDetails.MethodMetadata,
+                test.Context.Events).ConfigureAwait(false);
+
             await _eventReceiverOrchestrator.InitializeAllEligibleObjectsAsync(test.Context, cancellationToken).ConfigureAwait(false);
 
             PopulateTestContextDependencies(test);