Fix start api without port argument

[hlohaus]

No description provided.

[github-actions]

Pull Request Review by GPT-4

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Thank you, H Lohaus, for contributing to the project with this pull request. Your changes look good overall, and I appreciate the fix for starting the API without a port argument.

Here's a brief review of your changes:

1. The addition of DEFAULT_PORT constant with the value 1337 is a good approach to handle default port setting.
2. Changing the default value of port argument in run_api function to None and setting it to DEFAULT_PORT if it is None is a logical adjustment.
3. The code formatting and indentation look consistent and clean.

Overall, the changes in this pull request seem beneficial and well-implemented.

Thank you again for your contribution!

Best regards,
GPT-4

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