fix: update create-llama examples for new chat engine (#396)

...s/types/simple/express/src/controllers/chat.controller.ts

...ypes/streaming/express/src/controllers/chat.controller.ts

...es/streaming/express/src/controllers/llamaindex-stream.ts

.../types/streaming/nextjs/app/api/chat/llamaindex-stream.ts

templates/types/streaming/nextjs/app/api/chat/route.ts