Fixed bounce rate on stats page (#21097)

closes
https://linear.app/tryghost/issue/ANAL-81/investigate-bounce-rate-looks-incorrect

- Think I've figured out what was wrong
- TODO: Figure out TinyBird's test pipeline, so we can verify this

ghost/admin/app/components/stats/kpis-overview.js

@@ -96,7 +96,7 @@ export default class KpisOverview extends Component {
             avg_session_sec: Math.floor(_ponderatedKPIsTotal('avg_session_sec') / 60),
             pageviews: formatNumber(_KPITotal('pageviews')),
             visits: formatNumber(totalVisits),
-            bounce_rate: _ponderatedKPIsTotal('bounce_rate').toFixed(2)
+            bounce_rate: (_ponderatedKPIsTotal('bounce_rate') * 100).toFixed(0)
         };
     }
 

ghost/tinybird/pipes/kpis.pipe

@@ -147,7 +147,7 @@ SQL >
         a.date as date,
         sum(b.visits) as visits,
         sum(b.pageviews) as pageviews,
-        sum(b.bounce_rate) as bounce_rate,
+        avg(b.bounce_rate) as bounce_rate,
         sum(b.avg_session_sec) as avg_session_sec
     from timeseries a
     left join data b using date