Further fixes

* fixes race condition on geometry conflict calculation if performed in background process
* simplifies access to smaller buffered geometry
* adds mapping of "qm"->"m2" for UnitChoice in API usage for backwards compatibility

api/utils/serializer/v1/serializer.py

@@ -392,7 +392,8 @@ class AbstractCompensationAPISerializerV1Mixin:
                 self._konova_code_from_json(e, CODELIST_COMPENSATION_ACTION_DETAIL_ID) for e in entry["action_details"]
             ]
             amount = float(entry["amount"])
-            unit = entry["unit"]
+            # Mapping of old "qm" into "m²"
+            unit = UnitChoices.m2.value if entry["unit"] == "qm" else entry["unit"]
             comment = entry["comment"]
 
             # Check on validity