fix: import from correct path

`RecordItem`-import was added when we moved to ruff
(and type-annotated all the things as ruff requires type-annotations)
afaict, the previously used import-path never existed...

invenio_records_lom/oai.py

@@ -11,7 +11,7 @@
 from invenio_pidstore.errors import PIDDoesNotExistError
 from invenio_pidstore.models import PersistentIdentifier
 from invenio_records_resources.services.errors import PermissionDeniedError
-from invenio_records_resources.services.result import RecordItem
+from invenio_records_resources.services.records.results import RecordItem
 
 from .proxies import current_records_lom
 from .resources.serializers import LOMToOAIXMLSerializer