Update comment in update_data_provider

Co-authored-by: Matthias Kuhn <[email protected]>

libqfieldsync/offliners.py

@@ -296,9 +296,8 @@ def update_data_provider(layer: QgsVectorLayer, source: str) -> None:
     layer.setCustomProperty(CUSTOM_PROPERTY_ORIGINAL_LAYERID, layer.id())
     layer.setCustomProperty(CUSTOM_PROPERTY_LAYERNAME_SUFFIX, "")
 
-    # TODO: review this code, why do we connect defaultvalueclause to not null constraints?
-    #
-    # remove constrainst of fields that use defaultValueClauses from provider on original
+    # Remove constraints from fields that have a default value provided by the "online" provider.
+    # Example: a user should not be forced to enter an autogenerated primary key in offline mode, compare https://github.com/qgis/QGIS/issues/28122
     not_null_field_names = []
     source_fields = layer.fields()
     for field in source_fields: