fix(GODT-3124): Handling of sync child jobs

Improve the handling of sync child jobs to ensure it behaves correctly
in all scenarios.

The sync service now uses a isolated context to avoid all the pipeline
stages shutting down before all the sync tasks have had the opportunity
to run their course.

The job waiter now immediately starts with a counter of 1 and waits
until all the child and the parent job finish before considering the
work to be finished.

Finally, we also handle the case where a sync job can't be queued
because the calling context has been cancelled.

internal/bridge/bridge.go

@@ -307,7 +307,7 @@ func newBridge(
 		bridge.heartbeat.init(bridge, heartbeatManager)
 	}
 
-	bridge.syncService.Run(bridge.tasks)
+	bridge.syncService.Run()
 
 	return bridge, nil
 }
@@ -451,6 +451,8 @@ func (bridge *Bridge) Close(ctx context.Context) {
 		logrus.WithError(err).Error("Failed to close servers")
 	}
 
+	bridge.syncService.Close()
+
 	// Stop all ongoing tasks.
 	bridge.tasks.CancelAndWait()