chore(examples): fix chainlit example (#3223)

The commit updates the message content in the `main.py` file of the
chatbot example.

# Description

Please include a summary of the changes and the related issue. Please
also include relevant motivation and context.

## Checklist before requesting a review

Please delete options that are not relevant.

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented hard-to-understand areas
- [ ] I have ideally added tests that prove my fix is effective or that
my feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged

## Screenshots (if appropriate):

Author: StanGirard

backend/core/examples/chatbot/main.py

@@ -19,7 +19,7 @@ async def on_chat_start():
 
     file = files[0]
 
-    msg = cl.Message(content=f"Processing `{file.name}`...", disable_feedback=True)
+    msg = cl.Message(content=f"Processing `{file.name}`...")
     await msg.send()
 
     with open(file.path, "r", encoding="utf-8") as f:

backend/core/examples/simple_question.py

@@ -1,8 +1,8 @@
 import tempfile
 
 from quivr_core import Brain
-from quivr_core.quivr_rag import QuivrQARAG
 from quivr_core.quivr_rag_langgraph import QuivrQARAGLangGraph
+    
 
 if __name__ == "__main__":
     with tempfile.NamedTemporaryFile(mode="w", suffix=".txt") as temp_file:
@@ -18,6 +18,3 @@
             "what is gold? asnwer in french", rag_pipeline=QuivrQARAGLangGraph
         )
         print("answer QuivrQARAGLangGraph :", answer.answer)
-
-        answer = brain.ask("what is gold? asnwer in french", rag_pipeline=QuivrQARAG)
-        print("answer QuivrQARAG :", answer.answer)