Move normalization of JSON to a Python script

What does this MR do?

More the normalization of JSON in the end-to-end tests to a Python script. Python is much easier to read and write than jq and moving everything to one place reduces repetition in the tests.

What are the relevant issue numbers?

This MR is related to #209315

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Job definition example
  • Vendored CI Templates (also in CE)
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer