[Services] Remove Arc usage

Summary:
Arc allows for the release of resources to be delegated to the runtime.
However, we have a global singleton which will always be in scope, so we don't
have to worry about it needing to be dynamically released.

https://linear.app/comm/issue/ENG-1732

Test Plan: Backup CI passes

Reviewers: max, karol, varun, atul, tomek

Reviewed By: max

Subscribers: ashoat, abosh

Differential Revision: https://phab.comm.dev/D5114