Remove fake changelog entries

What does this MR do?

Fake changelog entries were generated as part of testing our release tooling with the main branch. Now that the testing is done, this commit removes such entries.

More info on gitlab-com/gl-infra/delivery#1441 (closed)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content