fix: support specifying a facet by its column index

Currently the Clarify BiasConfig only accepts facet name. Actually
Clarify analysis configuration supports both name and index. This
commit adds the same support to BiasConfig.

Author: xgchena

tests/unit/test_clarify.py

@@ -82,19 +82,6 @@ def test_invalid_data_config():
         )
 
 
-def test_s3_data_distribution_type_ignorance():
-    data_config = DataConfig(
-        s3_data_input_path="s3://input/train.csv",
-        s3_output_path="s3://output/analysis_test_result",
-        label="Label",
-        headers=["Label", "F1", "F2", "F3", "F4"],
-        dataset_type="text/csv",
-        joinsource="F4",
-        s3_data_distribution_type="ShardedByS3Key",
-    )
-    assert data_config.s3_data_distribution_type == "FullyReplicated"
-
-
 def test_bias_config():
     label_values = [1]
     facet_name = "F1"