Fixed use of where.not with multiple fields

The behavior of this is going to change in Rails 6.1
where.not(a: 1, b: 2) is going to be:

WHERE (a != 1 OR b !=2 ) instead of WHERE (a != 1 AND b != 2)

app/models/notification_setting.rb

@@ -21,7 +21,10 @@ class NotificationSetting < ApplicationRecord
   # pending delete).
   #
   scope :for_projects, -> do
-    includes(:project).references(:projects).where(source_type: 'Project').where.not(projects: { id: nil, pending_delete: true })
+    includes(:project).references(:projects)
+      .where(source_type: 'Project')
+      .where.not(projects: { id: nil })
+      .where.not(projects: { pending_delete: true })
   end
 
   EMAIL_EVENTS = [