Change icon to button on environment folder

What does this MR do and why?

Instead of the collapse/expand icon being just an icon, we can make it more accessable by making it a button.

Screenshots or screen recordings

How to set up and validate locally

1. Enable the new environments page

   Feature.enable(:new_environments_table)

2. Navigate to <gdk>/h5bp/html5-boilerplate/-/environments/new and create at least 2 environments with the same prefix, e.g. review/foo and review/bar.
3. Navigate to environments page
4. View folder item

MR acceptance checklist

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

• I have evaluated the MR acceptance checklist for this MR.