Remove ess-R-object-popup from ess layer.
Remove ess-R-object-popup from ess layer.

As described in issue #9464, this package was removed from melpa for
not having a GPL compatible license and is causing an error every time
spacemacs starts.

tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs,tsonntag/dotemacs