🐛(provisioning) fix unique count queries aggregation

For unique (complete) views, aggregation was based on the actors.
However, it was incorrect as the metric is a unique count on them.
Furthermore, the number of views displayed was limited to 500.
To be correct, the aggregation needs to be based on the video ids.

src/dashboards/teachers/course.jsonnet

@@ -238,7 +238,7 @@ dashboard.new(
       bucketAggs=[
         {
           id: 'name',
-          field: common.fields.actor_account_name,
+          field: common.fields.video_id,
           type: 'terms',
           settings: {
             order: 'desc',
@@ -340,7 +340,7 @@ dashboard.new(
       bucketAggs=[
         {
           id: '5',
-          field: common.fields.actor_account_name,
+          field: common.fields.video_id,
           type: 'terms',
           settings: {
             min_doc_count: '0',

src/dashboards/teachers/details.jsonnet

@@ -82,7 +82,7 @@ dashboard.new(
       bucketAggs=[
         {
           id: 'name',
-          field: common.fields.actor_account_name,
+          field: common.fields.video_id,
           settings: {
             order: 'desc',
             orderBy: '_count',
@@ -148,7 +148,7 @@ dashboard.new(
       bucketAggs=[
         {
           id: '5',
-          field: common.fields.actor_account_name,
+          field: common.fields.video_id,
           settings: {
             min_doc_count: '0',
             size: '0',