[identity] delete all data for user from otks table on account deletion

Summary:
get all of the device IDs for the user from the devices table. then call the method introduced in previous diff to delete all OTKs for each device

https://linear.app/comm/issue/ENG-7920/one-time-keys-are-not-deleted-during-logout-delete-rpcs

Depends on D11755

Test Plan: logged in and uploaded OTKs from multiple devices. then deleted my account on my native device and confirmed that all the OTKs were removed from staging DDB

Reviewers: bartek

Reviewed By: bartek

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D11756