Fix the permission

[yhaliaw]

Applicable spec:

Overview

Due to the failure in the workflow: https://github.com/canonical/github-runner-image-builder-operator/actions/runs/26495030820/job/78215639413

Error: Resource not accessible by integration
Error: HttpError: Resource not accessible by integration

Rationale

Juju Events Changes

Module Changes

Library Changes

Checklist

• The charm style guide was applied
• The contributing guide was applied
• The changes are compliant with ISD054 - Managing Charm Complexity
• The documentation for charmhub is updated.
• The PR is tagged with appropriate label (urgent, trivial, senior-review-required, documentation)
• The docs/changelog.md is updated with user-relevant changes in the format of keep a changelog v1.1.0
• The application version is incremented in app/pyproject.toml