#3591838 css variable name can be edited
This adds the ability to edit a Color's CSS var name vs only being able to set them on create
It also made the popovers scrollable as the increased height makes out-of-viewport more likely to occur
No designs available at the time of creating the MR. This uses the same styling as the create form.
Testing instructions
- Edit the CSS var name on an existing color
Closes #3591838 (closed)
