Refactor helper in environments controller for clarity

What does this MR do?

Swaps out the implementation of the environments controller helper method added in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24441

What are the relevant issue numbers?

#49388 (closed)

Does this MR meet the acceptance criteria?

• [n/a] Changelog entry added, if necessary
• [n/a] Documentation created/updated via this MR
• [n/a] Documentation reviewed by technical writer or follow-up review issue created
• [n/a] Tests added for this feature/bug
• [n/a] Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [n/a] Conforms to the database guides
• [n/a] Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• [n/a] Security reports checked/validated by reviewer