Allow user to disable PHP cached variants

[Gaya]

There are situations where pre-rendering variants in PHP will not work when there are caching plugins involved. The caching mechanism would be the one determining the variant instead of the user.

An option to always have JavaScript determine the variant would be better.

This could be done over XHR.

[themarblery]

I'm currently working on this issue and had a couple of questions:

• Is the goal to have a plugin setting that lets the user choose server-side or client-side rendering, or just always use client-side rendering? I started with a setting, but am running into issues where I feel like I am duplicating code across php and js, which doesn't feel right.
• It looks like a conversion is tracked when the goal is met at the page-level, not necessarily from the AB Testing Block itself. For example, if you put a link to the goal page within an AB Testing Block, and then then put the same link somewhere else on the same page (not in an AB Testing Block), a conversion is tracked if either of those links is clicked. Is this intended functionality? I don't want to cause any breaking changes, so just wanted to be sure.

Thanks for the help!