fix: do not mark call message as seen when accepting or declining a call

[link2xt]

When the message is marked as seen, an MDN (read receipt) is sent to self
and receiving such MDN marks all messages in the chat above the call message as noticed.
Calls may be accepted or declined from the notification,
so user may accept or decline a call without ever seeing a call message in the chat.

Closes #8631

[hpk42]

I am afraid I don't quite get the overall scheme of how caller/callee and their multi-device setups are meant to land in consistent states including UI notifications/interactions. I filed an issue #8635 and is it not strictly related to this particular PR.

For this PR my main concern is that the second device of the Callee might be left with a "Missed call" notifcation if there is no self-MDN anymore. As far as i see, at receiving time, a stale-on-arrival call notifies via

core/src/calls.rs

Lines 368 to 372 in 3784b3e

	if call.is_incoming() {
	if call.is_stale() {
	let missed_call_str = stock_str::missed_call(self);
	call.update_text(self, &missed_call_str).await?;
	self.emit_incoming_msg(call.msg.chat_id, call_id); // notify missed call

and i don't see what removes that notification afterwards.

The accepted-call path should probably be handled before #8631 can be closed but it doesn't necessarily block this PR i guess.

[hpk42]

This by itself does not send out anything, right?

[link2xt]

This just marks the message as noticed, as if you opened a chat with the message off the screen. Nothing is sent as a result and the message may still be marked as seen once the user opens the chat and the message appears on the screen, then MDN will be sent.

[link2xt]

For this PR my main concern is that the second device of the Callee might be left with a "Missed call" notifcation if there is no self-MDN anymore.

As far as I understand, this does not depend on MDNs. Declining a call (ending unaccepted call) sends SystemMessage::CallEnded, also as a copy to self if bcc_self (multi-device mode) is enabled. When second device receives it, it will turn the call into declined call:

core/src/calls.rs

Lines 463 to 468 in 322dd11

	if call.is_incoming() {
	if from_id == ContactId::SELF {
	call.mark_as_ended(self).await?;
	let declined_call_str = stock_str::declined_call(self);
	call.update_text(self, &declined_call_str).await?;
	} else {

If second device comes online much later, it should first receive "missed call", but then a copy of "call ended" message should turn it into declined call. UI may show "missed call" notification for a moment and should probably wait for IncomingMsgBunch event before showing any notifications to avoid notifying about missed call just before "call ended" arrives and it would be nice if the core postponed emitting "missed call" event until fetching is finished, but that's a separate problem.

The accepted-call path should probably be handled before #8631 can be closed but it doesn't necessarily block this PR i guess.

I fixed accepted calls as well, now only need to cleanup all SQL calls.