Add name_without_type to environments.json

What does this MR do?

Adds shorter name for environments in json response Needed to not duplicate folder name in the interface

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/24936

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Security reports checked/validated by reviewer