Revert "Ask for GitHub App OAuth and login connection during Org Code Host Connection (#32058)

Created by: mrnugget

This reverts commit b5cab0e4c26a29ebb7837cdabcfe1726ed86e95e.

I suspect that it broke main. Builds:

• https://buildkite.com/sourcegraph/sourcegraph/builds/135421 (build for PR that this is reverting)
• https://buildkite.com/sourcegraph/sourcegraph/builds/135427
• https://buildkite.com/sourcegraph/sourcegraph/builds/135431

Test plan

• CI on this PR
• main-dry-run build: https://buildkite.com/sourcegraph/sourcegraph/builds/135442