fix: add the needed CondenseQuestionChatEngine import in the usage_pa… (#8518)

* fix: add the needed CondenseQuestionChatEngine import in the usage_pattern docs

* Add entry to CHANGELOG.md

---------

Co-authored-by: Andrei Fajardo <92402603+nerdai@users.noreply.github.com>

CHANGELOG.md

 # ChangeLog
 
+## Unreleased
+
+### Bug Fixes / Nits
+
+- Add missing import to `ChatEngine` usage pattern `.md` doc (#8518)
+
 ## [0.8.53] - 2023-10-27
 
 ### New Features

docs/module_guides/deploying/chat_engines/usage_pattern.md

@@ -74,6 +74,7 @@ Here's an example where we configure the following:
 ```python
 from llama_index.prompts  import PromptTemplate
 from llama_index.llms import ChatMessage, MessageRole
+from llama_index.chat_engine.condense_question import CondenseQuestionChatEngine
 
 custom_prompt = PromptTemplate("""\
 Given a conversation (between Human and Assistant) and a follow up message from Human, \