chore: add more info in log (#614)

Author: dubin555

src/execution/live_updater.rs

@@ -252,10 +252,10 @@ impl FlowLiveUpdater {
         while let Some(result) = self.tasks.join_next().await {
             match result {
                 Err(e) if !e.is_cancelled() => {
-                    error!("{:?}", e);
+                    error!("A background task in FlowLiveUpdater failed to join: {:?}", e);
                 }
                 Ok(Err(e)) => {
-                    error!("{:?}", e.context("Error in applying changes from a source"));
+                    error!("Error reported by a source update task during live update: {:?}", e);
                 }
                 _ => {}
             }