If a user saves a Github personal access token in the creation flow and then re-enters after the token has been revoked, they should receive in appropriate error message.

Repro Steps

1. Navigate to /create-pipeline
2. Select "Github"
3. Enter a valid Github access token
4. Navigate to Github and revoke the access token
5. Navigate to /create-pipeline again
6. Select "Github"

Expected Behavior
User should be prompted to enter a new access token. Ideally the user should get some feedback that it appears the credential is invalid.

Actual Behavior
"Loading" message displays forever. http://localhost:8080/jenkins/blue/rest/organizations/jenkins/scm/github/organizations/?credentialId=github 500 (Server Error)

{
  "message" : "Server returned HTTP response code: 401, message: 'Unauthorized' for URL: https://api.github.com/user",
  "code" : 500,
  "errors" : [ ]
}