Fix error displayed when insights files can't be found and fix server-report insights in dev build (#18635)

* Fix error

* fix queries

extensions/server-report/sql/cpumetric.sql

@@ -0,0 +1,25 @@
+   -- source: https://sqlserverperformance.wordpress.com/2009/07/30/how-to-get-sql-server-cpu-utilization-from-a-query/
+   -- Use for a demo/sample purpose only. This query is not built-in to any product.
+   
+   DECLARE @ts_now bigint = (SELECT cpu_ticks/(cpu_ticks/ms_ticks)FROM sys.dm_os_sys_info); 
+
+    SELECT  Top(30) 'CPU%' as [label],
+            DATEADD(ms, -1 * (@ts_now - [timestamp]), GETDATE()) AS [Event Time],
+            SQLProcessUtilization AS [SQL Server Process CPU Utilization]
+                  -- SystemIdle AS [System Idle Process], 
+                  -- 100 - SystemIdle - SQLProcessUtilization AS [Other Process CPU Utilization],            
+    FROM ( 
+          SELECT record.value('(./Record/@id)[1]', 'int') AS record_id, 
+                record.value('(./Record/SchedulerMonitorEvent/SystemHealth/SystemIdle)[1]', 'int') 
+                AS [SystemIdle], 
+                record.value('(./Record/SchedulerMonitorEvent/SystemHealth/ProcessUtilization)[1]', 
+                'int') 
+                AS [SQLProcessUtilization], [timestamp] 
+          FROM ( 
+                SELECT [timestamp], convert(xml, record) AS [record] 
+                FROM sys.dm_os_ring_buffers 
+                WHERE ring_buffer_type = N'RING_BUFFER_SCHEDULER_MONITOR' 
+                AND record LIKE '%<SystemHealth>%') AS x 
+          ) AS y 
+    --ORDER BY record_id DESC;
+    ORDER BY [Event Time] DESC;