Edit Variant Button glitched

[AltayAkkus]

Bug report

When trying to edit a variant, the radix button is put under the next variant, so the UI becomes very ugly.

Describe the bug

The z-index set to the radix button does not work properly, because the parent element is neither position: relative nor does it have a own z-index set, so the z-index of the parent div is automatically higher than the highest child z-index, so our radix button is not shown over the elements.

System information

Medusa version (including plugins): demo.medusajs.com, so latest.
Node.js version: demo.medusajs.com
Database: demo.medusajs.com
Operating system: Windows 10
Browser (if relevant): Firefox (latest) and Chrome (latest)

Steps to reproduce the behavior

1. Go to demo.medusajs.com
2. Click on Variants -> Edit Variants
3. Click a random three-point menu
4. See error
   

Expected behavior

[AltayAkkus]

Should be fixed in #843