Remove wrong proxy resolver service code
Remove wrong proxy resolver service code

This was wrongly introduced in 44ba11517e99. This code is duplicated
from //electron/atom/utility/atom_content_utility_client.cc.

brave/electron,brave/electron,brave/muon,brave/electron,brave/muon,brave/muon,brave/electron,brave/electron,brave/muon,brave/muon,brave/electron,brave/muon