[ENH]: FastAPI Shutdown hook (chroma-core#1665)

## Description of changes

*Summarize the changes made by this PR.*
 - Improvements & Bug fixes
- On shutdown event system.stop() is called to properly stop all
components

## Test plan
*How are these changes tested?*

- [x] Tests pass locally with `pytest` for python

## Documentation Changes
N/A

chromadb/server/fastapi/__init__.py

@@ -141,6 +141,8 @@ def __init__(self, settings: Settings):
             allow_methods=["*"],
         )
 
+        self._app.on_event("shutdown")(self.shutdown)
+
         if settings.chroma_server_authz_provider:
             self._app.add_middleware(
                 FastAPIChromaAuthzMiddlewareWrapper,
@@ -280,6 +282,9 @@ def __init__(self, settings: Settings):
         use_route_names_as_operation_ids(self._app)
         instrument_fastapi(self._app)
 
+    def shutdown(self) -> None:
+        self._system.stop()
+
     def app(self) -> fastapi.FastAPI:
         return self._app