feat: Add EventType::CallMissed and emit it for missed calls (#7840)

Before, only `CallEnded` was emitted for missed calls, or, if a call arrives already being stale,
`IncomingMsg`. Now:
- `CallMissed` is emitted in addition to `CallEnded`.
- `IncomingMsg` is replaced with `CallMissed` for stale calls.
Having only one event type for missed calls should simplify handling them in the apps.

This doesn't emit `CallMissed` for those who aren't allowed to call us. Also, don't emit `CallEnded`
if the caller isn't allowed to call us and the call wasn't accepted, as there's no previous
`IncomingCall` event in this case.

deltachat-ffi/deltachat.h

@@ -6701,6 +6701,16 @@ void dc_event_unref(dc_event_t* event);
  */
 #define DC_EVENT_CALL_ENDED                               2580
 
+/**
+ * An incoming call was missed. Only emitted if the caller is allowed to call us. This happens when:
+ * - A call timed out (not accepted by us on time).
+ * - A call was canceled by the caller.
+ * - A stale call message was received, i.e. it is older than the timeout.
+ *
+ * This should trigger a UI notification.
+ */
+#define DC_EVENT_CALL_MISSED                              2590
+
 /**
  * Transport relay added/deleted or default has changed.
  * UI should update the list.

deltachat-ffi/src/lib.rs

@@ -556,6 +556,7 @@ pub unsafe extern "C" fn dc_event_get_id(event: *mut dc_event_t) -> libc::c_int
         EventType::IncomingCallAccepted { .. } => 2560,
         EventType::OutgoingCallAccepted { .. } => 2570,
         EventType::CallEnded { .. } => 2580,
+        EventType::CallMissed { .. } => 2590,
         EventType::TransportsModified => 2600,
         #[allow(unreachable_patterns)]
         #[cfg(test)]
@@ -626,6 +627,7 @@ pub unsafe extern "C" fn dc_event_get_data1_int(event: *mut dc_event_t) -> libc:
         | EventType::IncomingCallAccepted { msg_id, .. }
         | EventType::OutgoingCallAccepted { msg_id, .. }
         | EventType::CallEnded { msg_id, .. } => msg_id.to_u32() as libc::c_int,
+        EventType::CallMissed { msg_id, .. } => msg_id.to_u32() as libc::c_int,
         EventType::ChatlistItemChanged { chat_id } => {
             chat_id.unwrap_or_default().to_u32() as libc::c_int
         }
@@ -679,6 +681,7 @@ pub unsafe extern "C" fn dc_event_get_data2_int(event: *mut dc_event_t) -> libc:
         | EventType::WebxdcRealtimeAdvertisementReceived { .. }
         | EventType::OutgoingCallAccepted { .. }
         | EventType::CallEnded { .. }
+        | EventType::CallMissed { .. }
         | EventType::EventChannelOverflow { .. }
         | EventType::TransportsModified => 0,
         EventType::MsgsChanged { msg_id, .. }
@@ -796,7 +799,9 @@ pub unsafe extern "C" fn dc_event_get_data2_str(event: *mut dc_event_t) -> *mut
             let data2 = accept_call_info.to_c_string().unwrap_or_default();
             data2.into_raw()
         }
-        EventType::CallEnded { .. } | EventType::EventChannelOverflow { .. } => ptr::null_mut(),
+        EventType::CallEnded { .. }
+        | EventType::CallMissed { .. }
+        | EventType::EventChannelOverflow { .. } => ptr::null_mut(),
         EventType::ConfigureProgress { comment, .. } => {
             if let Some(comment) = comment {
                 comment.to_c_string().unwrap_or_default().into_raw()