Consistently treat tinyint(1) fields in message database as booleans (#2380)

* Update mysql2 query call to cast booleans

* Treat messages:held field as boolean

* Treat messages:inspected field as boolean

* Treat messages:spam field as boolean

* Treat messages:threat field as boolean

* Treat messages:bounce field as boolean

* Treat messages:received_with_ssl field as boolean

* Treat deliveries:sent_with_ssl field as boolean

api/structures/delivery_api_structure.rb

@@ -3,7 +3,7 @@ structure :delivery do
   basic :status
   basic :details
   basic :output, value: proc { o.output&.strip }
-  basic :sent_with_ssl, value: proc { o.sent_with_ssl == 1 }
+  basic :sent_with_ssl, value: proc { o.sent_with_ssl }
   basic :log_id
   basic :time, value: proc { o.time&.to_f }
   basic :timestamp, value: proc { o.timestamp.to_f }