Fix publish job dry_run handling for schedule trigger

[blink1073]

Summary

• publish job used inputs.dry_run directly, which is empty/undefined when triggered by schedule
• Apply the same ternary pattern already used by the release job: github.event_name == 'schedule' && 'true' || inputs.dry_run

Test plan

• Verify scheduled runs set skip-existing and verbose to true in the publish step
• Verify workflow_dispatch runs still respect the dry_run input