HOLI-6604 instantiate chatClient only once

src/handlers/space-created-handler.ts

src/handlers/space-updated-handler.ts

src/handlers/space-user-left-handler.ts

src/helpers/_chatClient.ts

src/helpers/createSpace.ts

src/helpers/kickUserFromSpace.ts

src/helpers/rooms.ts

src/index.ts

start-chat-integration-local.sh

terraform/environments/function.tf