[widgets][assetwidget] Update the declaration on successful algorithm migration

Only the code was updated

beat/editor/widgets/assetwidget.py

@@ -492,6 +492,7 @@ class AssetWidget(QWidget):
                     status, asset = migrate_to_api_v2(asset)
                     if status:
                         update_code(asset)
+                        declaration = asset.declaration
                     else:
                         QMessageBox.information(
                             self,