[CI][NFC] Format files with Black

The incremental formatter with darker seems to leave behind some issues
around how many lines of whitespace between certain constructs.

Author: boomanaiden154

.ci/metrics/metrics.py

@@ -70,6 +70,7 @@
 # by trial and error).
 GRAFANA_METRIC_MAX_AGE_MN = 120
 
+
 @dataclass
 class JobMetrics:
     job_name: str
@@ -243,6 +244,7 @@ def clean_up_libcxx_job_name(old_name: str) -> str:
     new_name = stage + "_" + remainder
     return new_name
 
+
 def github_get_metrics(
     github_repo: github.Repository, last_workflows_seen_as_completed: set[int]
 ) -> tuple[list[JobMetrics], int]:

.ci/metrics/metrics_test.py

@@ -409,5 +409,6 @@ def test_clean_up_libcxx_job_name(self):
         out_name4 = metrics.clean_up_libcxx_job_name(bad_name)
         self.assertEqual(out_name4, bad_name)
 
+
 if __name__ == "__main__":
     unittest.main()