RED-198334 Bump GH Actions off Node 20 (release/8.6)

[gonen-red]

Summary

RED-198334. Cherry-pick of the canonical Node 20 -> Node 24 bump from unstable (#526). Targets release/8.6.

• Bump first-party actions: actions/checkout@v4 -> @v6 (16 sites), actions/upload-artifact@v4 -> @v7 (5 sites), actions/download-artifact@v4 -> @v7
• Bump docker/* actions: setup-buildx v3->v4 (3 sites), login v3->v4 (4 sites), build-push v6->v7 (2 sites)
• Bump dorny/test-reporter v2->v3, peter-evans/create-pull-request v7->v8, iarekylew00t/verified-bot-commit v1->v2

Test plan

• pull-request.yml runs cleanly on this PR
• On next release tag, release_build_and_test.yml produces same image digests with bumped actions

---

Note

Medium Risk
Touches the full PR, nightly, and release publish pipelines; regressions would show as workflow failures rather than image changes, but release tagging and official-images PR steps depend on these actions.

Overview
Cherry-pick onto release/8.6 (RED-198334) to move CI off GitHub Actions that depend on Node 20, aligning with the bump already on unstable (#526). Only composite actions and workflow YAML change—no Dockerfiles, Redis build logic, or runtime behavior.

First-party actions: actions/checkout v4 → v6 across PR, build/test, release, and composite steps; actions/upload-artifact v4 → v7 and actions/download-artifact v4 → v7 for metadata, release handles, and failure logs.

Docker & tooling: docker/setup-buildx-action v3 → v4, docker/login-action v3 → v4, docker/build-push-action v6 → v7; plus dorny/test-reporter v2 → v3, peter-evans/create-pull-request v7 → v8, and iarekylew00t/verified-bot-commit v1 → v2 in release automation paths.

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[Peter-Sh]

Thanks, I did it by merging your unstable PR into release branches.