webhooks: Migrate most integrations to use check_send_webhook_message.

This commit migrates all of our webhooks to use
check_send_webhook_message, except the following:

beeminder: Rishi wanted to wait on this one.
teamcity: This one is slightly more work.

yo: This one is PM-only. I am still trying to decide whether we
    should have a force_private argument or something in
    check_send_webhook_message.

facebook: No point in migrating this, will be removed as part of
          #8433.

slack: Slightly more work too with the `channel_to_topics` feature.
       Warrants a longer discussion.

zerver/webhooks/intercom/view.py

@@ -4,16 +4,15 @@ from typing import Any, Dict, Text
 from django.http import HttpRequest, HttpResponse
 
 from zerver.decorator import api_key_only_webhook_view
-from zerver.lib.actions import check_send_stream_message
 from zerver.lib.request import REQ, has_request_variables
 from zerver.lib.response import json_success
+from zerver.lib.webhooks.common import check_send_webhook_message
 from zerver.models import UserProfile
 
 @api_key_only_webhook_view('Intercom')
 @has_request_variables
 def api_intercom_webhook(request: HttpRequest, user_profile: UserProfile,
-                         payload: Dict[str, Any] = REQ(argument_type='body'),
-                         stream: Text = REQ(default='intercom')) -> HttpResponse:
+                         payload: Dict[str, Any] = REQ(argument_type='body')) -> HttpResponse:
     topic = payload['topic']
     topic = topic.replace('.', ' ')
 
@@ -26,5 +25,5 @@ def api_intercom_webhook(request: HttpRequest, user_profile: UserProfile,
                 ' - User Email: {}\n' \
                 ' - User Phone: {}\n'.format(data['name'], data['email'], data['phone'])
 
-    check_send_stream_message(user_profile, request.client, stream, topic, body)
+    check_send_webhook_message(request, user_profile, topic, body)
     return json_success()