[services] Tunnelbroker - Change AmqpManager.send() method arguments to use MessageItem

Summary:
This diff introducing changes in AmqpManager.send() method to use MessageItem instead of arguments list.

Linear task: ENG-1214

Test Plan: Run tests from D4512

Reviewers: karol, tomek

Reviewed By: karol, tomek

Subscribers: ashoat, tomek, adrian, atul, karol, abosh

Differential Revision: https://phab.comm.dev/D4511