Refactor end-to-end test

What does this MR do?

Refactor end-to-end test to be explicit when fabricating resources via API or browser UI, and to improve test speed by fabricating some resources via API instead of via the GUI.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content