tests: adjust for a recent fix

In 67c366e (cascading-run: check the correct `app` attribute,
2025-11-25), I addressed a bug where real-life, non-mocked Check Run
events would not have a top-level `app` attribute, but it would be
hidden inside the `check_run` attribute.

I forgot to update the mocked events in the tests to reflect that
reality, and therefore the tests failed ever since (and I did not even
notice because this repository has no dependencies that Dependabot
would open PRs for, and the actual code is robust enough that there is
no real need to open other PRs).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

__tests__/index.test.js

@@ -793,7 +793,10 @@ test('a completed `tag-git` run triggers `git-artifacts` runs', async () => {
                 title: 'Tag Git v2.40.0-rc1.windows.1 @c8edb521bdabec14b07e9142e48cab77a40ba339',
                 summary: 'Tag Git v2.40.0-rc1.windows.1 @c8edb521bdabec14b07e9142e48cab77a40ba339',
                 text: 'For details, see [this run](https://github.com/git-for-windows/git-for-windows-automation/actions/runs/4322343196).\nTagged Git v2.40.0-rc1.windows.1\nDone!.'
-            }
+            },
+            app: {
+                slug: 'gitforwindowshelper',
+            },
         },
         installation: {
             id: 123
@@ -991,7 +994,10 @@ test('the third completed `git-artifacts-<arch>` check-run triggers an `upload-s
                 title: 'Build Git v2.48.0-rc2.windows.1-472-g0c796d3013-20250128120446 artifacts',
                 summary: 'Build Git v2.48.0-rc2.windows.1-472-g0c796d3013-20250128120446 artifacts from commit 0c796d3013a57e8cc894c152f0200107226e5dd1 (tag-git run #13009996573)',
                 text: 'For details, see [this run](https://github.com/git-for-windows/git-for-windows-automation/actions/runs/13010016895).'
-            }
+            },
+            app: {
+                slug: 'gitforwindowshelper',
+            },
         },
         installation: {
             id: 123