feat: remove constants.ts in ts templates

packages/create-llama/templates/index.ts

.../create-llama/templates/types/simple/express/constants.ts

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

...eate-llama/templates/types/streaming/express/constants.ts

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

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

...es/types/streaming/nextjs/app/components/chat-section.tsx

...reate-llama/templates/types/streaming/nextjs/constants.ts