pytorch

adc54dc2 - Give better error message when merge fails to find any rules (#84160)

Give better error message when merge fails to find any rules (#84160) Fixes #84147 and https://github.com/pytorch/test-infra/issues/421. * If merge rule file is missing or fails to load for whatever reasons: ``` No rules find to match PR, please [report]{issue_link} this issue to DevX team. ``` * If the list of rules is empty: ``` Merges are not allowed into repository without a rules. ``` Pull Request resolved: https://github.com/pytorch/pytorch/pull/84160 Approved by: https://github.com/ZainRizvi, https://github.com/malfet