Revert new_environments_dropdown GlTokenSelector migration

Ezekiel Kigborequested to merge
revert-3edd3e39 into master

What does this MR do and why?

Reverts Migrate GlDropdown in app/assets/javascripts/fe... (#384273 - closed) while we investigate some bugs the change introduced.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

Merge request reports