drape_electrodes_on_topography breaking with 3D survey inputs

[JKutt]

simpeg/SimPEG/electromagnetics/static/resistivity/survey.py

Line 178 in c63e699

loc_a = self.locations_a

It would appear that variables from lines 178 to 181 previously took in (x,2) locations from a 3D input of (x,3). Now it takes the (x,3) and the drapeTopotoLoc then throws the error "shape of pts should be (x,3)" If I modify lines 178 to 181 to take just (x,2) all goes back to working order.

In any case attached is a notebook re-creating the problem which may be more helpful.
test_drape_locations.zip