differentiate support for tips in study

Studies show up as supporting a tip if they have that genus as a tip, even though they have no spp level information 

e.g.
https://tree.opentreeoflife.org/opentree/opentree13.4@ott3597211/Setophaga-citrina

https://tree.opentreeoflife.org/curator/study/view/ot_1174?tab=home&tree=tree3&node=node70