[Dev] PR automation workflow fails to identify committers that have a different alias for ASF and GitHub

### Describe the bug, including details regarding any error messages, version, and platform.

The [committers.yml file on the arrow-site repository](https://github.com/apache/arrow-site/blob/main/_data/committers.yml) contains information about the PMC and committers for the Arrow project. The current information is:
```
- name: committer name
role: VP/PMC/committer
alias: ASF alias
affiliation: Work affiliation
```
We assumed the [alias on the committers file was the GitHub id](https://github.com/apache/arrow/pull/34557) instead of the ASF id. In general this is working because lots of members use the same ASF id than their GitHub id.
In some cases we are still not correctly identifying the committers.

See: https://github.com/apache/arrow-site/issues/338

### Component(s)

Developer Tools

Start with the committers.yml file in the arrow-site repository and the PR automation change referenced in Apache Arrow PR 34557. Compare how ASF aliases and GitHub IDs are represented, and review arrow-site issue 338 for related context. Done means the workflow correctly identifies committers whose ASF and GitHub aliases differ.

Written by the indexing model from the issue text.