feat: Mark reactions as IMAP-seen in marknoticed_chat(), second try

[Hocuri]

Instead of being trashed, the message containing a reaction remains in the chat, hidden and InFresh. When the chat is opened, it will be marked as Seen on the server, so that a second device removes the notifications for the reaction.

This is a more minimal alternative to #6213, trying to keep things simpler.

Close #6210.

Also, this adds a benchmark.

[Hocuri]

Performance matters here because this is done in the "hot path" of the user opening a chat. This could be replaced by:

        context
            .sql
            .transaction(|trans| {
                trans.execute(
                    "UPDATE msgs SET state=? WHERE state=? AND hidden=1 AND chat_id=?",
                    (MessageState::InSeen, MessageState::InNoticed, chat_id),
                )?;
                trans.execute(
                    "INSERT OR IGNORE INTO imap_markseen (id)
                    SELECT id FROM imap WHERE rfc724_mid IN
                    (SELECT rfc724_mid FROM msgs WHERE state=? AND hidden=1 AND chat_id=?)",
                    (MessageState::InNoticed, chat_id),
                )?;
                Ok(())
            })
            .await?;
        context.scheduler.interrupt_inbox().await;

However, in my benchmark, this actually has worse performance:

Probably because the messages have to be loaded twice now. Also, this always opens a write connection, not only when messages actually have to be marked as noticed.

If you know of a possibly more performant version of this, tell me & I'll benchmark it. But the most important part is the SELECT statement anyway, since it's the only thing that will be executed even if no messages are fresh.

Maybe I'll make update_msg_state() and markseen_on_imap_table() take a transaction in a subsequent PR, maybe this improves the (benchmark) performance.