[lib] check timestamps before processing delete entry operation

Summary:
Checks timestamps to unsure delete operation isn't alread out of date. If it is, produces a no-op update.

Depends on D13347

Test Plan: As previous, unsure yet how to test this. Will update test plan later

Reviewers: marcin, ashoat, tomek

Reviewed By: tomek

Differential Revision: https://phab.comm.dev/D13348