remove the word Optional from description

lesson_graph.py

@@ -96,7 +96,7 @@ class LessonGraph:
 
         for field, node_type in optional_nodes.items():
             if self.inputs.get(field):
-                nodes[self.inputs[field]] = {"type": node_type, "description": f"Optional {node_type.value}"}
+                nodes[self.inputs[field]] = {"type": node_type, "description": f"{node_type.value}"}
 
         # Add nodes to the graph
         for node, attributes in nodes.items():