Correction test erroné dans le template de la vue "admin"

Ref: #17853 @20m

tmpl/admin.yaml

@@ -219,7 +219,7 @@ tabs:
             scheduling: true
             hybrid: true
             other: true
-%if %%getVar('activer_oneflow','non')
+%if %%oneflow
     oneflow-templates-tab:
         panel_tabs:
             service_template_info_tab: true