Silent CI failures due to enforced action restrictions with no prior notice

**Continuation of #550** *(closed; unable to reopen)*

This issue focuses specifically on verified actions **silently failing** in GitHub workflows following the recently enforced policies.

## Problem

Several GitHub workflows are now failing silently as a result of the new action restrictions. For example: https://github.com/apache/iceberg-python/actions/runs/23416549033

These failures are marked with **"Status: Startup failure"** and the following error:
```
The action pypa/cibuildwheel@v3.4.0 is not allowed in apache/iceberg-python because all actions
must be from a repository owned by your enterprise, created by GitHub, or match one of the
allowed patterns.
```

While it's great to see efforts to improve ASF's security posture, it would be really helpful to have some advance notice before changes like this are enforced, so projects aren't caught off guard.

## Impact

* CI silently drops checks due to enforcement — see [#550 (comment)](https://github.com/apache/infrastructure-actions/issues/550#issuecomment-4101119993) — with no indication that workflows have failed.
* No notifications are sent when GitHub workflows stop working. The failed nightly run linked above was only discovered by manually checking the **Actions** tab. This project has [CI job notifications configured](https://lists.apache.org/list.html?ci-jobs@iceberg.apache.org), yet no alerts were received.

## Solution
EDIT: Added a new github action (`apache/infrastructure-actions/allowlist-check@main`) to address this issue, https://github.com/apache/infrastructure-actions/pull/587