Revert "Revert "Implement stateful and deferrable notification decryption and use it on iOS in NSE""

Summary:
This reverts commit 56c0498aa0a3c415243be9097eedd673a6dc38c1.

Depends on D9559

Test Plan: This is bringing back @marcin's D9401. Changes to fix the resulting bug (ENG-5354) will follow in subsequent diffs.

Reviewers: marcin, tomek, bartek, atul

Reviewed By: marcin

Subscribers: wyilio, marcin

Differential Revision: https://phab.comm.dev/D9560