feat: add validation to prevent duplicate global environment names (fixes: #3449)

[Pragadesh-45]

fixes: #3449

Description

This PR implements logic to check for the existence of duplicate names under global environments to prevent name conflicts.

Contribution Checklist:

• [x] The pull request only addresses one issue or adds one feature.
• [x] The pull request does not introduce any breaking changes
• [x] I have added screenshots or gifs to help explain the change if applicable.
• [x] I have read the contribution guidelines.
• [x] Create an issue and link to the pull request.

Before:

https://github.com/user-attachments/assets/12d17ff2-9cdd-4e18-9fb0-57367ff2df31

After:

https://github.com/user-attachments/assets/f3ee88fe-eff9-4165-8fe6-fbfbd78d6f5f