Encrypt notifications for Windows users with code version high enough to support this feature

Summary: This differential uses encryption API implemented in parent differential to encrypt windows notifications assuming that the client passes introduced code version checks. Additionally a one-liner change is introduced in desktop code that enables Windows clients to handle encrypted notifications.

Test Plan:

1. Setup ngrok tunneling for http://localhost:3000
2. Build windows desktop app following detailed instructions from: https://linear.app/comm/issue/ENG-5859/set-up-environment-for-windows-application-development
3. Replace NEXT_CODE_VERSION in version-utils.js with 1 and all isStaffOrDev in cookies.js and send.js with true. (the reason is that to test Windows we have to use production build of the keyserver.
4. Connect from Windows app to the keyserver. Ensure that new row in olm_sessions is created.
5. Send notifications to Windows client. Ensure that version field of the row created in previous step increments with each notification and each notification is displayed correctly.

Reviewers: michal, kamil

Reviewed By: michal

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D10194