UX Audit - Add optional descriptions to multivariate options

### Is your feature request related to a problem? Please describe.

Variation values can either act as the name of the variation (like version “a” and “b”), or act as the values of what’s different in the test (e.g. the color of the button for each variation). But I only have one value to set, rather than separate name and value fields.

### Describe the solution you'd like.


Much like segment rules, we should let multivariate options have a description. This could get cluttered so I think we do exactly the same as segments in toggling this on or off


### Describe alternatives you've considered

N/A

### Additional context

_No response_