Buttons give option "others" after ask the question

domain.yml

forms:

  • user_feedback responses: utter_ask_hear:
  • text: “Where did you hear from us?” buttons:
    • title: “LinkedIn” payload: “1”
    • title: “amazon” payload: “2”
    • title: “Google” payload: “3”
    • title: “Friends” payload: “4”
    • title: “Neighbours” payload: “5”
    • title: “Employees” payload: “6”
    • title: “Others” payload: “6”

slots: hear: auto_fill: false type: unfeaturized

If I clicking the option button “others” after that will it ask question like type your answer… How can I achieve that? How can I validate that from slots or something. Thanks in advance.