Coupon Box Experiment Code Clean Up

[briowill]

Related to #
#93516
#95364

Proposed Changes

Remove unused code related to experiment

Why are these changes being made?

We have concluded the hide coupon box experiment and now need to remove unused code related to the test.

Testing Instructions

1. Apply branch
2. Navigate to the checkout eg. *http://calypso.localhost:3000/start
3. Confirm you are seeing the Have a coupon section

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-5e75f8b6b7033ed534f5332702f61bd0eb5f79d0

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-5e75f8b6b7033ed534f5332702f61bd0eb5f79d0&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-5e75f8b6b7033ed534f5332702f61bd0eb5f79d0&env=a8c-for-agencies

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

App Entrypoints (~77 bytes removed 📉 [gzipped])

name         parsed_size           gzip_size
entry-main        -176 B  (-0.0%)      -77 B  (-0.0%)
entry-login       -176 B  (-0.0%)      -77 B  (-0.0%)

Common code that is always downloaded and parsed every time the app is loaded, no matter which route is used.

Sections (~243 bytes removed 📉 [gzipped])

name      parsed_size           gzip_size
checkout       -681 B  (-0.0%)     -243 B  (-0.0%)

Sections contain code specific for a given set of routes. Is downloaded and parsed only when a particular route is navigated to.

Async-loaded Components (~386 bytes removed 📉 [gzipped])

name                                                                              parsed_size           gzip_size
async-load-calypso-my-sites-checkout-modal                                             -857 B  (-0.1%)     -322 B  (-0.1%)
async-load-calypso-blocks-editor-checkout-modal                                        -681 B  (-0.1%)     -243 B  (-0.1%)
async-load-signup-steps-page-picker                                                    -380 B  (-0.1%)     -160 B  (-0.1%)
async-load-purchase-modal-wrapper                                                      -380 B  (-0.1%)     -160 B  (-0.1%)
async-load-my-sites-checkout-purchase-modal-is-eligible-for-one-click-checkou...       -380 B  (-0.1%)     -160 B  (-0.1%)

React components that are loaded lazily, when a certain part of UI is displayed for the first time.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.