receipts/add: Skip updating notes if unchanged

If the value of the `notes` form field is the same as the current value
for the same field of an existing Firefly transaction, we do not need to
update it.

src/routes/receipts.rs

@@ -128,9 +128,13 @@ pub async fn add_receipt(
                         needs_update = true;
                     }
                     if !data.notes.is_empty() {
+                        if let Some(notes) = split.notes.as_deref() {
+                            if notes != data.notes.as_str() {
                                 split.notes = Some(data.notes.clone());
                                 needs_update = true;
                             }
+                        }
+                    }
                 } else {
                     debug!("Transaction {} has no splits", id);
                 }