Replace rqr-rails3 gem

What does this MR do and why?

Solves #387373 (closed)

We are replacing gem - rqrcode-rails3 with core rqrcode gem.

Current rqrcode-rails3 gem is unmaintained had last commit some 10 years ago. While core gem rqrcode gem is highly maintained with an active contributor community. rqrcode-rails3 gem is built upon rqrcode-rails gem itself with some minimal syntactical sugar - #387373 (comment 1359606898) .

We can safely replace the gem.

Screenshots or screen recordings

final UI Rendered after discussion with @mvanremmerden

We can see some rendering difference in before and after screenshot, this is due to the reason that rqrcode-rails3 gem is using very old version of rqrcode which is 0.7 current version of rqr-code is 2.0 which has some difference in the way svg size is determined. The rendering difference is minimal in my opinion but we can still take an input from a frontend person here.

These are the ealier version of UI tried updated Gem

Before	After	With 3.8 module size

How to set up and validate locally

1. Run bundle install for the new gem update to take place
2. Visit page https://gdk.test:3443/-/profile/two_factor_auth to check the new rendering of QR code

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.