Updates churn example to use correct port for UI

[hsubbaraj-spiral]

Describe your changes and why you are making these changes

Updates the churn example notebook to use port 8080 instead of 3000.

Related issue number (if any)

Checklist before requesting a review

• I have created a descriptive PR title. The PR title should complete the sentence "This PR...".
• I have performed a self-review of my code.
• [n/a] I have included a small demo of the changes. For the UI, this would be a screenshot or a Loom video.
• [n/a] If this is a new feature, I have added unit tests and integration tests.
• [n/a] I have run the integration tests locally and they are passing.
• [n/a] All features on the UI continue to work correctly.
• [n/a] Added one of the following CI labels:
  • run_integration_test: Runs integration tests
  • skip_integration_test: Skips integration tests (Should be used when changes are ONLY documentation/UI)

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[cw75]

@hsubbaraj-spiral could you do a rebase with main. Thx!