when Pr pipeline is disabled, PR does not actually go through the pr pipeline, but the PR result is shown as "pass", so pr reviewer would misunderstand the pr is ok to be merged, which might cause "false pass" issue.

enhancement would be: when pr pipeline is disabled, give PR result a default "fail" in PR check result.

Steps to reproduce it:

1. set up any PR pipeline which is triggered by webhook in a github repo
2. disable this PR pipeline
3. when PR created in github repo,  PR does not actually go through the pr pipeline, but the PR result is shown as "pass"