This commit adds an endpoint `/mobile_push/e2ee/test_notification`
to send an end-to-end encrypted test push notification to the user's
selected mobile device or all of their mobile devices.
This commit updates the data that gets encrypted to be
the same on both android and iOS.
The data and its format is almost the same as what we send
as FCM payload to android clients with no E2EE support,
changes are:
For send push notification payload:
* 'realm_id`, 'server', 'sender_email', and 'realm_uri' fields
don't exist in the new payload.
* 'event' field renamed to 'type'
* 'stream' and 'stream_id' fields renamed to 'channel_name'
and 'channel_id' respectively.
* The value of 'recipient_type' will be 'channel' & 'direct'
instead of 'stream' & 'private' respectively.
* 'zulip_message_id' field renamed to 'message_id'
For remove push notification payload:
* 'realm_id`, 'server', and 'realm_uri' fields don't exist
in the new payload.
* 'event' field renamed to 'type'
* 'zulip_message_ids' field renamed to 'message_ids' and it's
value will be a JSON array instead of a string.
In the existing iOS client, we have no code of our own involved
in constructing the notifications in the UI, and instead we
leave it to the iOS SDK to do so.
Since, for clients with E2EE support the data is going to be
interpreted by our own code, not by the iOS SDK - we are free
to keep the same data and format.
Co-authored-by: Tim Abbott <tabbott@zulip.com>
