scheduler: Always dequeue high priority repos for update.
Created by: ryanslade
Before, when disableAutoGitUpdates was set we would stop our update scheulder. Now, we always run the scheduler but when disableAutoGitUpdates is set we only handle repos flagged as high priority. In practice, these are repos added from outside out scheduler, specifically from the refresh webhook.
This allows customers to disable our scheduler but continue to manually update repos when required.
Fixes: https://github.com/sourcegraph/customer/issues/109 Fixes: https://github.com/sourcegraph/customer/issues/371