Fix draft store operations

Summary: Current implementation of draft store operations creation and processing does not obey new policy regarding cancellable asynchronous tasks and tries to access 'payload' property of draft store operation object even if the operation is of type 'remove_all' and does not contain this property. This results in app crashes when logging out.

Test Plan: Build native app on top of https://phab.comm.dev/D5712. Log out - see that app crashes. Apply this differential. See that application does not crash and succesfully logs out.

Reviewers: tomek, kamil, jon

Reviewed By: tomek

Subscribers: ashoat, atul

Differential Revision: https://phab.comm.dev/D5731