Fixes #714. Do not show the cellular graphs if there is no ppp interface defined.
Fixes #714. Do not show the cellular graphs if there is no ppp interface defined.

ch1c4um/pfsense,BlackstarGroup/pfsense,NewEraCracker/pfsense,NewEraCracker/pfsense,ptorsten/pfsense,NOYB/pfsense,jxmx/pfsense,ch1c4um/pfsense,brunostein/pfsense,phil-davis/pfsense,NewEraCracker/pfsense,brunostein/pfsense,ptorsten/pfsense,ch1c4um/pfsense,phil-davis/pfsense,pfsense/pfsense,BlackstarGroup/pfsense,dennypage/pfsense,jxmx/pfsense,jxmx/pfsense,BlackstarGroup/pfsense,dennypage/pfsense,dennypage/pfsense,NewEraCracker/pfsense,NOYB/pfsense,pfsense/pfsense,ptorsten/pfsense,phil-davis/pfsense,pfsense/pfsense,NOYB/pfsense,ch1c4um/pfsense,dennypage/pfsense,BlackstarGroup/pfsense,phil-davis/pfsense,brunostein/pfsense,pfsense/pfsense