Use release-bot token for cross-repo API calls in getsentry org workflows

The sentry-internal-app is NOT installed on all getsentry repos (e.g. sentry-xbox, sentry-playstation, sentry-switch, service-registry). Using its token for cross-repo API calls like gh api repos/{other-repo}/commits/... returns 404 "Not Found" — looks like a missing resource but is actually a missing installation. Use sentry-release-bot instead: configure with client-id: ${{ vars.SENTRY_RELEASE_BOT_CLIENT_ID }}, private-key: ${{ secrets.SENTRY_RELEASE_BOT_PRIVATE_KEY }}, and owner: getsentry to get a token with access to all org repos. Pattern in getsentry/publish CI poller: generate both tokens, use internal-app for publish-repo label changes, release-bot for cross-repo repos/{repo}/commits/{sha}/status and /check-runs API calls.