Update Renovate reviewer teams

[nerrad]

Fixes #

Proposed changes

• Route Renovate review requests to the Jetpack product teams responsible for the affected features.
• Keep both Jetpack Newsletter and Loop as reviewers for bundled WordPress dependency updates.
• Keep QualityOps as an additional reviewer for GitHub Actions updates alongside the global Jetpack Monorepo reviewer.
• Keep the dependency groupings and update behavior unchanged; this only changes reviewer routing.

PR #50868 also changes the bundled WordPress package rule and may require this branch to be rebased after it lands.

Related product discussion/links

• None.

Does this pull request change what data or activity we track or use?

No.

Testing instructions

• Confirm every team:* reviewer in .github/renovate.json5 resolves to a GitHub team with access to Automattic/jetpack.
• Run pnpm lint-file .github/renovate.json5.
• Run pnpm exec prettier --check .github/renovate.json5.
• Confirm the next relevant Renovate pull requests request the applicable product teams, while Newsletter updates continue to request both Jetpack Newsletter and Loop.

*left by Biff (AI agent) on behalf of Darren

[github-actions]

Thank you for your PR!

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