Add FF to include more users in conditional alerts

* By default if the target of a conditional alert is a location,
  it is only send to users that have this location as their primary
  location.
* With the new FF enabled all users that are assigned to the location
  are included no matter, if it is their primary or a secondary
  location.

corehq/messaging/scheduling/scheduling_partitioned/models.py

@@ -2,9 +2,11 @@
 import pytz
 import sys
 import uuid
+
+from corehq import toggles
 from corehq.apps.casegroups.models import CommCareCaseGroup
 from corehq.apps.groups.models import Group
-from corehq.apps.locations.dbaccessors import get_all_users_by_location
+from corehq.apps.locations.dbaccessors import get_all_users_by_location, user_ids_at_locations
 from corehq.apps.locations.models import SQLLocation
 from corehq.apps.sms.models import MessagingEvent
 from corehq.apps.users.cases import get_owner_id, get_wrapped_owner
@@ -24,6 +26,7 @@
 from datetime import timedelta, date, datetime, time
 from memoized import memoized
 from dimagi.utils.couch import get_redis_lock
+from dimagi.utils.couch.database import iter_docs
 from dimagi.utils.modules import to_function
 from django.db import models
 from django.conf import settings
@@ -191,7 +194,14 @@ def expand_group(group):
     def expand_location_ids(domain, location_ids):
         user_ids = set()
         for location_id in location_ids:
-            for user in get_all_users_by_location(domain, location_id):
+            if toggles.INCLUDE_ALL_LOCATIONS.enabled(domain):
+                user_ids_at_this_location = user_ids_at_locations([location_id])
+                users = [CouchUser.wrap_correctly(u)
+                         for u in iter_docs(CouchUser.get_db(), user_ids_at_this_location)]
+            else:
+                users = get_all_users_by_location(domain, location_id)
+
+            for user in users:
                 if user.is_active and user.get_id not in user_ids:
                     user_ids.add(user.get_id)
                     yield user

corehq/toggles/__init__.py

@@ -2977,3 +2977,11 @@ def domain_has_privilege_from_toggle(privilege_slug, domain):
     tag=TAG_CUSTOM,
     namespaces=[NAMESPACE_DOMAIN],
 )
+
+INCLUDE_ALL_LOCATIONS = StaticToggle(
+    slug='include_all_locations',
+    label='USH: When sending conditional alert that target locations expand them to users that are assigned to '
+          'the location no matter if it is their primary location or not.',
+    tag=TAG_CUSTOM,
+    namespaces=[NAMESPACE_DOMAIN],
+)