[lib][native] Merge decryption types into media mission types

Summary:
Previously, the "decryption" step/failure types were separated from media mission types.
I need them to be merged in order to be able to add a new "decryption" step in the media mission when saving multimedia.

Simply moved them to media-types.js and updated fuction types accordingly.

Depends on D10852

Test Plan: Flow

Reviewers: atul, ashoat

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D10853