[PP-1] Remove BetterConfigExistsContraint and move back to ConfigExistsContraint

Thanks for creating this issue! 😄

This was blocked by ✨ The ConfigExists validation constraint should support dynamic replacement tokens Active , which is marked as fixed. However at the time of writing it's not released in (at least not in 11.2.2).

Ah, I bet that's because it didn't make the cut-off for 11.2 😬

So this must be 11.3-only. Updating title accordingly. Sorry about that.