[lib][web][native] Make all the props of StoreOperations optional

Summary:
Before this diff we had to create objects with all the fields present even when most of them were empty arrays. This diff makes creating the ops object more convenient.

Depends on D11933

Test Plan: Tested if processing the ops still works on web and native by checking if drafts get persisted.

Reviewers: kamil, marcin

Reviewed By: kamil

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D11936