Revert "Clean up external service updating UI code (#2033)"
Created by: tsenart
This reverts commit 62a0bb3e94a75fc6126c8e5dfaabbe92bbc2a9c5.
Reverting this commit fixes the weird behaviour I reported in https://github.com/sourcegraph/sourcegraph/issues/2227.
I don't know exactly why, because my TypeScript skills are lacking and I'd go down a rabbit hole to debug this.
Fixes #2227 (closed)