Remove unneeded jsondiff output parsing

Why these changes are being introduced:

Now that the DeepDiff library provides an explicit list of
modified "root" fields -- i.e. TIMDEX fields -- as a built-in
property, we no longer need any additional logic to parse the diff
and surface what fields were modified.

How this addresses that need:
* This removes the helper function generate_field_diff_bools_for_record()
and any tests related to it.

Side effects of this change:
* None

Relevant ticket(s):
* https://mitlibraries.atlassian.net/browse/TIMX-373

abdiff/core/calc_ab_metrics.py

@@ -104,32 +104,6 @@ def create_record_diff_matrix_dataset(
     return metrics_dataset
 
 
-def generate_field_diff_bools_for_record(diff_data: dict) -> dict:
-    """Function to return dictionary of fields that have a diff.
-
-    Determining if a field had a diff is as straight-forward as looking to see if it shows
-    up in the parsed diff JSON.  The fields may be at the root of the diff, or they could
-    be nested under "$insert" or "$delete" nodes in the diff.
-
-    If a field from the original A/B records are not in the diff at all, then they did not
-    have changes, and therefore will not receive a 1 here to indicate a diff.
-    """
-    fields_with_diffs = {}
-
-    for key in diff_data:
-
-        # identify modified fields nested in $insert or $delete blocks
-        if key in ("$insert", "$delete"):
-            for subfield in diff_data[key]:
-                fields_with_diffs[subfield] = 1
-
-        # identified modified fields at root of diff
-        else:
-            fields_with_diffs[key] = 1
-
-    return fields_with_diffs
-
-
 def calculate_metrics_data(field_matrix_parquet: str) -> dict:
     """Create a dictionary of metrics via DuckDB queries."""
     summary: dict = {}

tests/test_calc_ab_metrics.py

@@ -12,32 +12,10 @@
     calc_ab_metrics,
     calculate_metrics_data,
     create_record_diff_matrix_dataset,
-    generate_field_diff_bools_for_record,
 )
 from abdiff.core.utils import load_dataset, read_run_json
 
 
-def test_record_field_diffs_no_diffs():
-    diff_data = {}
-    assert generate_field_diff_bools_for_record(diff_data) == {}
-
-
-def test_record_field_diffs_one_diff():
-    diff_data = {"color": "green"}
-    assert generate_field_diff_bools_for_record(diff_data) == {"color": 1}
-
-
-def test_record_field_diffs_diff_from_inserts_and_deletes_counted_only_once():
-    diff_data = {
-        "$insert": {"fruits": "strawberry"},
-        "$delete": {"vegetables": "onion"},
-    }
-    assert generate_field_diff_bools_for_record(diff_data) == {
-        "fruits": 1,
-        "vegetables": 1,
-    }
-
-
 def test_sparse_matrix_dataset_created_success(run_directory, diffs_dataset_directory):
     diff_matrix_dataset_filepath = create_record_diff_matrix_dataset(
         run_directory, diffs_dataset_directory