Possibly unintended synchronisation of ReceiptMessage

[hrdl-github]

As described in whisperfish/presage#290 (comment), gurk/presage triggers https://github.com/signalapp/Signal-Android/blob/0891a161b2d2b5de819f98d829370a8f12e7c124/libsignal-service/src/main/java/org/whispersystems/signalservice/api/messages/EnvelopeContentValidator.kt#L195 ([DataMessage] Missing timestamp!) in other clients. I believe this to be due to libsignal-service-rs trying to synchronising ReceiptMessages

libsignal-service-rs/src/sender.rs

Line 416 in 6401dc3

if needs_sync || is_multi_device {

, leaving not much more than the field unidentifiedStatus.