fix: Reset message error when scheduling resending (#5119)

Before, while a message is in OutPending state after resending is requested, the user still sees the
red marker with error and it is confusing, so the user don't know the sending state of the message.

src/receive_imf/tests.rs

@@ -689,6 +689,9 @@ async fn test_resend_after_ndn() -> Result<()> {
         )
         .await;
     chat::resend_msgs(&t, &[msg_id]).await?;
+    let msg = Message::load_from_db(&t, msg_id).await?;
+    assert_eq!(msg.state, MessageState::OutPending);
+    assert_eq!(msg.error(), None);
     // Alice receives a BCC-self copy of their message.
     receive_imf(
         &t,