Revert "Update statsd-mapping.yml to support Airflow 2.X pool metrics (…

…apache#36305)" (apache#36959)

This reverts commit 3e6d69d. This is a
breaking change in the way metrics are exported.

chart/files/statsd-mappings.yml

@@ -82,18 +82,8 @@ mappings:
     labels:
       pool: "$1"
 
-  - match: airflow.pool.queued_slots.*
-    name: "airflow_pool_queued_slots"
-    labels:
-      pool: "$1"
-
-  - match: airflow.pool.running_slots.*
-    name: "airflow_pool_running_slots"
-    labels:
-      pool: "$1"
-
-  - match: airflow.pool.deferred_slots.*
-    name: "airflow_pool_deferred_slots"
+  - match: airflow.pool.used_slots.*
+    name: "airflow_pool_used_slots"
     labels:
       pool: "$1"