fix a typo in example file dag-conditional-artifacts.yaml

[TCGOGOGO]

Tips:

• Maybe add you organization to USERS.md.
• Your PR needs to pass the required checks before it can be approved. If the check is not required (e.g. E2E tests) it does not need to pass
• Sign-off your commits to pass the DCO check: git commit --signoff.
• Run make pre-commit -B to fix codegen or lint problems.
• Say how how you tested your changes. If you changed the UI, attach screenshots.
• If changes were requested, and you've made them, then dismis the review to get it looked at again.
• You can ask for help!

[terrytangyuan]

Great catch.