fix(ci): pass WF_GITHUB_TOKEN to checkout for git fetch and PR creation

[davidoliv1]

Summary

• Passes WF_GITHUB_TOKEN to the actions/checkout step in the S3 multi-environment deploy workflow

Motivation

Steps that run git fetch origin main stage and gh pr create need a checkout with credentials that can access the repository. The default GITHUB_TOKEN may be insufficient for cross-branch git operations and PR creation in reusable workflows.

Changes

• Add with.token: ${{ secrets.WF_GITHUB_TOKEN }} to the Checkout step in build_and_upload_to_s3

Test plan

• Trigger stage deploy with create_pr_in_main: true on a consumer repo
• Confirm git fetch origin main stage succeeds in the workflow logs
• Confirm PR creation from stage to main works when conditions are met