chore: apply least privilege permissions to github actions

[yasnagat]

Proposed changes

This PR applies the principle of least privilege to GITHUB_TOKEN permissions across all GitHub Actions workflows by setting permissions: {} globally and explicitly re-granting only the minimum permissions required per job, as part of a supply chain security hardening effort.

Workflows relied on GitHub’s default token scopes, which may grant more access than most jobs actually need. Scoping permissions at the job level reduces the attack surface in the event that a GitHub Action, third-party dependency, or CI component is compromised, helping mitigate the impact of potential supply chain attacks and limiting unnecessary repository access.

This change only affects the permissions granted to the workflow GITHUB_TOKEN. Operations authenticated using explicitly configured Personal Access Tokens (PATs) continue to have the scopes assigned to those tokens and are not affected by workflow permissions settings.

Issue(s)

SB-975

[github-actions]

Created PR on the official-images repo (docker-library/official-images#21780). See https://github.com/docker-library/faq#an-images-source-changed-in-git-now-what if you are wondering when it will be available on the Docker Hub.