Update auto-update-app-headers.yml: Enable auto approval

[michelroegl-brunner]

✍️ Description

Update the app header workflow to auto-approv its own work.

✅ Prerequisites

The following steps must be completed for the pull request to be considered:

• [] Self-review performed (I have reviewed my code to ensure it follows established patterns and conventions.)
• [] Testing performed (I have thoroughly tested my changes and verified expected functionality.)

🛠️ Type of Change

Please check the relevant options:

• [] Bug fix (non-breaking change that resolves an issue)
• [] New feature (non-breaking change that adds functionality)
• [] Breaking change (fix or feature that would cause existing functionality to change unexpectedly)
• [] New script (a fully functional and thoroughly tested script or set of scripts)

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📋 Additional Information (optional)

Provide any extra context or screenshots about the feature or fix here.