fix(model): properly health-check up-to-date folders (fixes #10546) (#10773)

Previously we'd skip the health check for an up-to-date folder, so it
would continue looking up-to-date even when the folder path missing.

---------

Signed-off-by: Jakob Borg <jakob@kastelo.net>

lib/model/folder_sendrecv.go

@@ -168,7 +168,6 @@ func (f *sendReceiveFolder) pull(ctx context.Context) (bool, error) {
 	go f.pullScannerRoutine(ctx, scanChan)
 	defer func() {
 		close(scanChan)
-		f.setState(FolderIdle)
 	}()
 
 	metricFolderPulls.WithLabelValues(f.ID).Inc()