fix: Send pre-message after successful sending of post-message (#8063)

Also, send the message text in the post-message too, we can't support the workaround for duplicated
message text shown in ancient versions anymore, otherwise newer versions won't show the message text
at all.

On the receiving side, download post messages w/o known pre-message after 30s to protect from lost
messages.

This isn't easy to test in Rust though because the `smtp` sending code requires an SMTP connection,
so it's only tested (by already existing tests) that messages are queued in the right order.

Another problem is that the `smtp` sending logic doesn't try to send any messages following a
failed-to-send message until the retry limit is reached, so if there's smth wrong with a
post-message, other unrelated messages are delayed, but this problem has already existed.

src/tests/pre_messages/forward_and_save.rs

@@ -106,7 +106,7 @@ async fn test_receive_both() -> Result<()> {
     assert_eq!(msg.text, "test".to_owned());
 
     forward_msgs(alice, &[alice_msg_id], alice_chat_id).await?;
-    let rev_order = false;
+    let rev_order = true;
     let msg = bob
         .recv_msg(
             &alice

src/tests/pre_messages/receiving.rs

@@ -257,7 +257,7 @@ async fn test_lost_pre_msg() -> Result<()> {
     let _pre_msg = alice.pop_sent_msg().await;
     let msg = bob.recv_msg(&full_msg).await;
     assert_eq!(msg.download_state, DownloadState::Done);
-    assert_eq!(msg.text, "");
+    assert_eq!(msg.text, "populate");
     Ok(())
 }
 
@@ -547,8 +547,8 @@ async fn test_webxdc_updates_in_post_message_after_pre_message() -> Result<()> {
         .await?;
 
     send_msg(alice, alice_chat_id, &mut alice_instance).await?;
-    let post_message = alice.pop_sent_msg().await;
     let pre_message = alice.pop_sent_msg().await;
+    let post_message = alice.pop_sent_msg().await;
 
     let bob_instance = bob.recv_msg(&pre_message).await;
     assert_eq!(bob_instance.download_state, DownloadState::Available);
@@ -588,8 +588,8 @@ async fn test_webxdc_updates_in_post_message_without_pre_message() -> Result<()>
         .await?;
 
     send_msg(alice, alice_chat_id, &mut alice_instance).await?;
-    let post_message = alice.pop_sent_msg().await;
     let pre_message = alice.pop_sent_msg().await;
+    let post_message = alice.pop_sent_msg().await;
 
     // Bob receives post-message first.
     let bob_instance = bob.recv_msg(&post_message).await;