[VOL-4699] Fix panic in PM module in openonu-go adapter during Device Delete in Memory leak tests

Change-Id: I1baaa044ff311048d9ee3f6a5e368cdafe7220bc
diff --git a/internal/pkg/core/openonu.go b/internal/pkg/core/openonu.go
index 60d2f81..0069794 100755
--- a/internal/pkg/core/openonu.go
+++ b/internal/pkg/core/openonu.go
@@ -331,6 +331,9 @@
 		handler.deletionInProgress = true
 		handler.mutexDeletionInProgressFlag.Unlock()
 
+		// Setting the device deletion progress flag will cause the PM FSM to cleanup for GC after FSM moves to NULL state
+		handler.pOnuMetricsMgr.SetdeviceDeletionInProgress(true)
+
 		if err := handler.resetFsms(ctx, true); err != nil {
 			errorsList = append(errorsList, err)
 		}