Fix CurrentWorkerCount query

This was yielding all threads (whether they counted against max or not - giving a bad count). This properly gets only those that matter.

Opserver.Core/Data/SQL/SQLInstance.Properties.cs

@@ -115,7 +115,7 @@ Select Cast(SERVERPROPERTY(''ProductVersion'') as nvarchar(128)) Version,
        Cast(SERVERPROPERTY(''ProcessID'') as int) ProcessID,
        (Select Count(*) From sys.dm_exec_sessions) SessionCount,
        (Select Count(*) From sys.dm_exec_connections) ConnectionCount,
-       (Select Sum(current_workers_count) From sys.dm_os_schedulers) CurrentWorkerCount,
+       (Select Sum(active_workers_count)  From sys.dm_os_schedulers Where status = ''VISIBLE ONLINE'') CurrentWorkerCount,
        (Select Count(*) From msdb.dbo.sysjobs) JobCount,
        cpu_count CPUCount,
        hyperthread_ratio HyperthreadRatio,