Shared/Metric: Fix crash on shutdown

Fix crash on shutdown with metrics enabled but InfluxDB stopping before worldserver

(cherry picked from commit 45b2bcfaf2)

src/common/Metric/Metric.cpp

@@ -213,16 +213,17 @@ void Metric::ScheduleSend()
     }
 }
 
-void Metric::ForceSend()
+void Metric::Unload()
 {
     // Send what's queued only if IoContext is stopped (so only on shutdown)
     if (_enabled && Trinity::Asio::get_io_context(*_batchTimer).stopped())
     {
         _enabled = false;
         SendBatch();
-        _batchTimer->cancel();
-        _overallStatusTimer->cancel();
     }
+
+    _batchTimer->cancel();
+    _overallStatusTimer->cancel();
 }
 
 void Metric::ScheduleOverallStatusLog()