Revert "Revert "Ask for GitHub App OAuth and login connection during Org Code Host Connection (#32058)" (#32252)"

Created by: mrnugget

This reverts commit 5a9a429748e6e1e6f8e53427b6a474412922bd9d.

Turns out the 4 builds on main were flakes:

• https://buildkite.com/sourcegraph/sourcegraph/builds/135421#680e194f-bfc8-44aa-b52e-b8252eaad0f5
• https://buildkite.com/sourcegraph/sourcegraph/builds/135427#f625f9a8-435f-413e-9a0a-173b2c63c885
• https://buildkite.com/sourcegraph/sourcegraph/builds/135431#fc75bf4f-cafc-4f4d-91c0-6b3c5e461ec9
• https://buildkite.com/sourcegraph/sourcegraph/builds/135437#5f4a9ba4-1856-4bc4-922c-4c6fada3d68f

Test plan

• Buildkite