catch attempt to update missing note

https://forums.ankiweb.net/t/bug-report-editor-updating-non-existing-card/2117/4?u=dae

rslib/src/notes.rs

@@ -274,6 +274,8 @@ impl Collection {
                 // nothing to do
                 return Ok(());
             }
+        } else {
+            return Err(AnkiError::NotFound);
         }
 
         self.transact(None, |col| {