feat(agent_example): create prompt example to instruction

Author: floritange

veadk/prompts/prompt_example.py

@@ -18,7 +18,6 @@
 from google.adk.examples.example import Example
 
 
-# === Add these classes before the Agent class ===
 class FunctionCallExample(BaseModel):
     """Represents a function call output in an example."""