Make `check-enforcer` handle GH actions CI

[Example PR](https://github.com/Azure/azure-sdk-tools/pull/11441) checkenforcer never recognizes that the pipeline has a successful actions CI, so it stays in pending state.

We need to account for this in some way so that devs don't need to /check-enforcer override always.

Start with the check-enforcer entry point and compare its CI-status handling with the successful GitHub Actions run shown in example PR 11441. Trace why that status remains pending; done means check-enforcer recognizes a successful Actions CI without requiring /check-enforcer override, with coverage for the behavior if the existing test structure identifies a suitable place.

Written by the indexing model from the issue text.