fix(functions): remove duplicate region tag (#13426)

* fix(functions): remove duplicate region tag

This region tag is in this sample https://github.com/GoogleCloudPlatform/python-docs-samples/blob/main/functions/billing_stop_on_notification/stop_billing.py which causes this duplicate to not surface this sample.

* fix: clean up linting

Author: iennae

functions/billing/main.py

@@ -14,37 +14,28 @@
 
 # [START functions_billing_limit]
 # [START functions_billing_limit_appengine]
-# [START functions_billing_stop]
 # [START functions_billing_slack]
 import base64
 import json
 import os
-
-# [END functions_billing_stop]
 # [END functions_billing_limit]
 # [END functions_billing_limit_appengine]
 # [END functions_billing_slack]
 
 # [START functions_billing_limit]
 # [START functions_billing_limit_appengine]
-# [START functions_billing_stop]
 from googleapiclient import discovery
-
-# [END functions_billing_stop]
 # [END functions_billing_limit]
 # [END functions_billing_limit_appengine]
 
 # [START functions_billing_slack]
 import slack
 from slack.errors import SlackApiError
-
 # [END functions_billing_slack]
 
 # [START functions_billing_limit]
-# [START functions_billing_stop]
 PROJECT_ID = os.getenv("GCP_PROJECT")
 PROJECT_NAME = f"projects/{PROJECT_ID}"
-# [END functions_billing_stop]
 # [END functions_billing_limit]
 
 # [START functions_billing_slack]
@@ -86,7 +77,6 @@ def notify_slack(data, context):
 # [END functions_billing_slack]
 
 
-# [START functions_billing_stop]
 def stop_billing(data, context):
     pubsub_data = base64.b64decode(data["data"]).decode("utf-8")
     pubsub_json = json.loads(pubsub_data)
@@ -148,9 +138,6 @@ def __disable_billing_for_project(project_name, projects):
         print("Failed to disable billing, possibly check permissions")
 
 
-# [END functions_billing_stop]
-
-
 # [START functions_billing_limit]
 ZONE = "us-west1-b"