Test migration of sessions:
1. Open and lig in to web app before applying this diff.
2. Apply this diff and open web app again.
3. Check the content of indexed db and ensure that session and encryption key are stored under key that conforms to new format.
4. Depending on whether you are on old or new keyserver set-up you will or will not be able to decrypt notifs.
Test new session:
1. Open web app and ensure that you are logged out.
2. Log in.
3. Ensure that web notifs work correctly.
Test race condition:
1. Open logged out web app in three differenti windows.
2. Quickly log in to each.
3. Check that there are 6 entries in Indexed DB - 3 notifs sessions and 3 notifs sessions encryption keys.
4. Send a web notif.
5. Ensure that notif is correctly decrypted and displayed and after receiving notif there is only one notifs session in IndexedDB and one encryption key in IndexedDB
- both associated with largest cookie id value.