Remove --update_test_data flag
Summary of Changes
This leaked into the planemo command while I was setting up stdout/stderr for failed tests. It doesn't seem to do anything, but it may cause side effects that we should avoid if possible.
Checklist
- The MR has a clear and concise title
- Code is self-documented and follows style guidelines.
- Automated tests are written and pass successfully.
- Regression tests (e.g. manually triggered system tests, manual GUI/tool tests, ...) are performed to make sure the MR does not break anything (when applicable)
- Readme file is present and up-to-date.