Fix better_errors gem version and move it to web variant

[rafayet-monon]

What Happened

The current better_errors gem version is 2.8.2 which got some broken things that can be faced while creating a project using this rails-template. There Is an open PR regarding this issue which isn't merged yet. The error given is -

A recent CI fail can also be found here - https://nimble.semaphoreci.com/jobs/9b9da4fc-4176-490b-aa4c-0586bc8d710c

How to Fix

In this scenario should we can downgrade and fix the better_errors version till a new release arrives.

Also, better_errors is only used in web variant applications only. Should we move this to the web_variant in this case?

[rafayet-monon]

A recent better_errors version 2.8.3 was released on 3 Oct which implemented the fixes. Will open a different issue regarding better_errors being in web_variant. Closing this issue.