distinct query where fieldname points to nested _metadata attribute leads to 500

Reproduce:

Make a HTTP request using query-type 'distinct' and point fieldname to a nested _metadata attribute.

curl "localhost:6001/v0/query/studies?query_type=distinct" -H "Content-Type: application/json" --data '{"fieldname": "_metadata.schema_version"}'

Response:

{"code": 500, "message": "Internal Server Error"}

Docstore log:

Traceback (most recent call last):
  File "/kuha_document_store-env/lib/python3.12/site-packages/tornado/web.py", line 1790, in _execute
    result = await result
             ^^^^^^^^^^^^
  File "/kuha_document_store-env/lib/python3.12/site-packages/kuha_document_store/handlers.py", line 288, in post
    result = await self.get_db().query_distinct(collection, fieldname, _filter)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/kuha_document_store-env/lib/python3.12/site-packages/kuha_document_store/database.py", line 701, in query_distinct
    dig_and_set(results, path, datetime_to_datestamp, allow_none=True)
  File "/kuha_document_store-env/lib/python3.12/site-packages/kuha_common/document_store/records.py", line 142, in dig_and_set
    dig_and_set(item, path_join(*keys[index:]), replacement, allow_none)
  File "/kuha_document_store-env/lib/python3.12/site-packages/kuha_common/document_store/records.py", line 142, in dig_and_set
    dig_and_set(item, path_join(*keys[index:]), replacement, allow_none)
  File "/kuha_document_store-env/lib/python3.12/site-packages/kuha_common/document_store/records.py", line 142, in dig_and_set
    dig_and_set(item, path_join(*keys[index:]), replacement, allow_none)
  [Previous line repeated 986 more times]
  File "/kuha_document_store-env/lib/python3.12/site-packages/kuha_common/document_store/records.py", line 136, in dig_and_set
    keys = path_split(path)
           ^^^^^^^^^^^^^^^^
RecursionError: maximum recursion depth exceeded

Expected response would return distinct values of requested field.

This is actually a bug in Kuha Common and is fixed in kuha_common@080497ba