Look at your file:
from typing import Any, Text, Dict, List
from rasa_sdk import Action, Tracker
from rasa_sdk.executor import CollectingDispatcher
As you and your error say, there are indentation errors.
Be careful with spaces and indents in Python. It should be like that:
from typing import Any, Text, Dict, List
from rasa_sdk import Action, Tracker
from rasa_sdk.executor import CollectingDispatcher
Your whole file has wrong indents, not just that part.
I strongly suggest learning Python before jumping into Rasa. Good luck 