feat: Remove Config::SentboxWatch (#7178)

The motivation is to reduce code complexity, get rid of the extra IMAP connection and cases when
messages are added to chats by Inbox and Sentbox loops in parallel which leads to various message
sorting bugs, particularly to outgoing messages breaking sorting of incoming ones which are fetched
later, but may have a smaller "Date".

src/config.rs

@@ -156,10 +156,6 @@ pub enum Config {
     #[strum(props(default = "1"))]
     MdnsEnabled,
 
-    /// True if "Sent" folder should be watched for changes.
-    #[strum(props(default = "0"))]
-    SentboxWatch,
-
     /// True if chat messages should be moved to a separate folder. Auto-sent messages like sync
     /// ones are moved there anyway.
     #[strum(props(default = "1"))]
@@ -473,10 +469,7 @@ impl Config {
 
     /// Whether the config option needs an IO scheduler restart to take effect.
     pub(crate) fn needs_io_restart(&self) -> bool {
-        matches!(
-            self,
-            Config::MvboxMove | Config::OnlyFetchMvbox | Config::SentboxWatch
-        )
+        matches!(self, Config::MvboxMove | Config::OnlyFetchMvbox)
     }
 }
 
@@ -603,15 +596,6 @@ impl Context {
             || !self.get_config_bool(Config::IsChatmail).await?)
     }
 
-    /// Returns true if sentbox ("Sent" folder) should be watched.
-    pub(crate) async fn should_watch_sentbox(&self) -> Result<bool> {
-        Ok(self.get_config_bool(Config::SentboxWatch).await?
-            && self
-                .get_config(Config::ConfiguredSentboxFolder)
-                .await?
-                .is_some())
-    }
-
     /// Returns true if sync messages should be sent.
     pub(crate) async fn should_send_sync_msgs(&self) -> Result<bool> {
         Ok(self.get_config_bool(Config::SyncMsgs).await?
@@ -700,7 +684,6 @@ impl Context {
             | Config::ProxyEnabled
             | Config::BccSelf
             | Config::MdnsEnabled
-            | Config::SentboxWatch
             | Config::MvboxMove
             | Config::OnlyFetchMvbox
             | Config::DeleteToTrash