tests/unit_tests: sync unit tests after model changes (retry_counter field)

Changes [0] to the model caused unit tests to get out-of-sync with its
new state.

Tests adjusted in this patch should be kept in sync with Node class from
"kernelci/api/models.py" in "kernelci/kernelci-core" repo [1].

[0] kernelci/kernelci-core#2927
[1] https://github.com/kernelci/kernelci-core/blob/ee64d7e4cdaeef2176d9755c9112ff97c8ad8e3a/kernelci/api/models.py#L184

Signed-off-by: Paweł Wieczorek <pawiecz@collabora.com>

Author: pawiecz

tests/unit_tests/test_node_handler.py

@@ -88,6 +88,7 @@ def test_create_node_endpoint(mock_db_create, mock_publish_cloudevent,
         'updated',
         'user_groups',
         'processed_by_kcidb_bridge',
+        'retry_counter',
     }
 
 
@@ -249,6 +250,7 @@ def test_get_node_by_id_endpoint(mock_db_find_by_id,
         'updated',
         'user_groups',
         'processed_by_kcidb_bridge',
+        'retry_counter',
     }