Remove specific activity instance bookmarks

The change clears specific activity instance bookmarks in the context from the WorkflowExecutionContext. This is an extra step in the process of clearing bookmarks, which assists in managing and cleaning up workflow state effectively.

src/modules/Elsa.Workflows.Core/Extensions/ActivityExecutionContextExtensions.cs

@@ -504,6 +504,7 @@ public static class ActivityExecutionContextExtensions
 
         // Clear bookmarks.
         context.ClearBookmarks();
+        context.WorkflowExecutionContext.Bookmarks.RemoveWhere(x => x.ActivityInstanceId == context.Id);
 
         // Remove completion callbacks.
         context.ClearCompletionCallbacks();