fix: ci fails if no tests folder is added to python function

[cka-y]

Summary:

This pull request includes changes to the execute_python_tests() function in the scripts/api-tests.sh file to improve the logic for determining which directories should contain tests and to generate an error when it doesn't.

Improvements to test execution logic:
Error handling enhancements:

• scripts/api-tests.sh: Added error messages to handle cases where no tests directory is found in the subdirectories, improving the clarity of test execution failures.

• Run the unit tests with ./scripts/api-tests.sh to make sure you didn't break anything
• Add or update any needed documentation to the repo
• Format the title like "feat: [new feature short description]". Title must follow the Conventional Commit Specification(https://www.conventionalcommits.org/en/v1.0.0/).
• Linked all relevant issues
• Include screenshot(s) showing how this pull request works and fixes the issue(s)