Add workgroups metadata for activity_stream_bi (#1628)

* Add workgroups metadata for activity_stream_bi

* Update workgroup_access for activity_stream_bi

sql/moz-fx-data-shared-prod/activity_stream_bi/impression_stats_by_experiment_v1/metadata.yaml

@@ -10,3 +10,10 @@ labels:
   schedule: daily
 scheduling:
   dag_name: bqetl_activity_stream
+workgroup_access:
+  - role: roles/bigquery.dataViewer
+    members:
+      # to avoid permissions desync mozilla-confidential access is only granted
+      # at the dataset-level for now
+      # - workgroup:mozilla-confidential
+      - workgroup:pocket/external

sql/moz-fx-data-shared-prod/activity_stream_bi/impression_stats_flat_v1/metadata.yaml

@@ -8,3 +8,10 @@ labels:
   schedule: daily
 scheduling:
   dag_name: bqetl_activity_stream
+workgroup_access:
+  - role: roles/bigquery.dataViewer
+    members:
+      # to avoid permissions desync mozilla-confidential access is only granted
+      # at the dataset-level for now
+      # - workgroup:mozilla-confidential
+      - workgroup:pocket/external