Revert "Search backend: use client logger where applicable"

Created by: bobheadxi

Reverts sourcegraph/sourcegraph#38130 - see https://github.com/sourcegraph/sourcegraph/pull/38130#issuecomment-1174062463

tl;dr there appears to be a panic in main:

2022-07-04T16:14:23.456840216Z �[0;33m16:14:23                  frontend | �[0mpanic: runtime error: invalid memory address or nil pointer dereference
2022-07-04T16:14:23.456858647Z �[0;33m16:14:23                  frontend | �[0m[signal SIGSEGV: segmentation violation code=0x1 addr=0x50 pc=0x1f0281d]
2022-07-04T16:14:23.456865190Z �[0;33m16:14:23                  frontend | �[0mgoroutine 14292 [running]:
2022-07-04T16:14:23.456870463Z �[0;33m16:14:23                  frontend | �[0mgithub.com/sourcegraph/sourcegraph/internal/search/searcher.(*TextSearchJob).Run.func2.1()
2022-07-04T16:14:23.456875409Z �[0;33m16:14:23                  frontend | �[0m	github.com/sourcegraph/sourcegraph/internal/search/searcher/search.go:116 +0x75d

I will handle a fix and un-revert, but for now the tests are failing consistently at this point

Test plan: reverts to a known working state