feature: add analytics session ended_at to view

- Found that it wasn't possible to replicate the ["Average time spent"](https://metabase.editor.planx.uk/question/15-average-time-spent?flow_id=0e9d79ec-9cf3-497d-a1a1-8e70469bb52d) card without analytics session ended at
- Added this to the view

hasura.planx.uk/migrations/1702312905340_alter_view_analytics_summary_add_analytics_ended_at/down.sql

@@ -0,0 +1 @@
+DROP VIEW public.analytics_summary CASCADE;

hasura.planx.uk/migrations/1702312905340_alter_view_analytics_summary_add_analytics_ended_at/up.sql

@@ -0,0 +1,22 @@
+CREATE OR REPLACE VIEW "public"."analytics_summary" AS 
+ SELECT a.id AS analytics_id,
+    al.id AS analytics_log_id,
+    f.slug AS service_slug,
+    t.slug AS team_slug,
+    a.type AS analytics_type,
+    a.created_at AS analytics_created_at,
+    a.user_agent,
+    a.referrer,
+    al.flow_direction,
+    al.metadata,
+    al.user_exit AS is_user_exit,
+    al.node_type,
+    al.node_title,
+    al.has_clicked_help,
+    al.input_errors,
+    (date_part('epoch'::text, (al.next_log_created_at - al.created_at)))::numeric(10,1) AS time_spent_on_node_seconds,
+    a.ended_at AS analytics_ended_at
+   FROM (((analytics a
+     LEFT JOIN analytics_logs al ON ((a.id = al.analytics_id)))
+     LEFT JOIN flows f ON ((a.flow_id = f.id)))
+     LEFT JOIN teams t ON ((t.id = f.team_id)));