Correct gh aw logs syntax in cost-estimation workshop step

[Copilot]

The cost-estimation example in workshop/26-manage-costs-and-budgets.md used a non-existent --workflow flag for gh aw logs. This updates the workshop to match the current CLI, where the workflow name is passed positionally.

• Workshop command correction

  • Replaced the invalid named-flag form with the supported positional-argument form in the Estimate monthly cost for a scheduled workflow section.

• CLI example now matches current gh aw logs usage

  gh aw logs daily-status --count 5

• Fixes [workshop-sync] workshop/26-manage-costs-and-budgets.md: gh aw logs uses invalid --workflow flag #1885