fix: update session metrics in read_gbq_query (#1084)

* fix: update read_gbq_query query metric and fix ML transform metric missing issue.

* update test

Author: Genesis929

bigframes/session/loader.py

@@ -529,6 +529,9 @@ def read_gbq_query(
             configuration=configuration,
         )
 
+        if self._metrics is not None:
+            self._metrics.count_job_stats(query_job)
+
         # If there was no destination table, that means the query must have
         # been DDL or DML. Return some job metadata, instead.
         if not destination:

tests/system/large/ml/test_core.py

@@ -146,10 +146,15 @@ def test_bqml_standalone_transform(penguins_df_default_index, new_penguins_df):
             "ML.ONE_HOT_ENCODER(species, 'none', 1000000, 0) OVER() AS onehotencoded_species",
         ],
     )
+    start_execution_count = model.session._metrics.execution_count
+
+    transformed = model.transform(new_penguins_df)
+
+    end_execution_count = model.session._metrics.execution_count
+    assert end_execution_count - start_execution_count == 1
 
-    transformed = model.transform(new_penguins_df).to_pandas()
     utils.check_pandas_df_schema_and_index(
-        transformed,
+        transformed.to_pandas(),
         columns=["scaled_culmen_length_mm", "onehotencoded_species"],
         index=[1633, 1672, 1690],
         col_exact=False,