fix: do not interrupt IMAP loop from get_connectivity_html()

Android calls get_connectivity_html()
every time connectivity changes, which in turn interrupts
IMAP loop and triggers change from "not connected" to "connecting"
state.

To avoid such infinite loop of IMAP interrupts when
there is not connectivity, update quota only when IMAP
loop is interrupted otherwise. This anyway happens
when a message is received or maybe_network is called.

Also remove outdated comments about `Action::UpdateRecentQuota` job
which does not exist anymore.

src/sql.rs

@@ -742,8 +742,6 @@ pub async fn housekeeping(context: &Context) -> Result<()> {
         warn!(context, "Failed to deduplicate peerstates: {:#}.", err)
     }
 
-    context.schedule_quota_update().await?;
-
     // Try to clear the freelist to free some space on the disk. This
     // only works if auto_vacuum is enabled.
     match context