Fixes AI Platform example formatting in docs

[discdiver]

Closes PrefectHQ/prefect#13050 .

Example

Code now formats for docs.

Screenshots

After:

Checklist

• References any related issue by including "Closes #" or "Closes ".
  • If no issue exists and your change is not a small fix, please create an issue first.
• Includes tests or only affects documentation.
• Passes pre-commit checks.
  • Run pre-commit install && pre-commit run --all locally for formatting and linting.
• Includes screenshots of documentation updates.
  • Run mkdocs serve view documentation locally.

[desertaxle]

Thank you for your willingness to contribute to prefect-gcp! The code for this library has been moved to https://github.com/PrefectHQ/prefect/tree/main/src/integrations/prefect-gcp. Please reopen this PR there if this functionality is still needed!