Fixing a notebook history bug in SQL Agent (#1199)

* Added a leading 0 to notebook history runtimes

* Fixing comment

* Fix for getting run date and time for notebook jobs in a proper format - Try2

* Reverting back to previous query

src/Microsoft.SqlTools.ServiceLayer/Agent/Jobs/AgentNotebookHelper.cs

@@ -258,12 +258,11 @@ namespace Microsoft.SqlTools.ServiceLayer.Agent
             @"
             SELECT
             materialized_id,
-            run_time,
-            run_date,
             notebook_error,
             pin,
             notebook_name,
-            is_deleted
+            is_deleted,
+            FORMAT(msdb.dbo.agent_datetime(run_date, run_time), 'yyyyMMddHHmmss') as job_runtime 
             FROM 
             notebooks.nb_materialized 
             WHERE job_id = @jobId";