Update/remove coming soon option

[lsl]

Changes proposed in this Pull Request

• Disables the Coming Soon option in under the site settings privacy section if the config flag coming-soon-v2 is enabled.

Testing instructions

yarn run test-client:watch client/my-sites/site-settings/test/form-general.jsx

I've added some basic test coverage but this one probably needs some manual testing to double check the transition works properly.

The below should behave the same regardless of v2 being enabled (e.g. define( 'WPCOM_PUBLIC_COMING_SOON', true ); )

Should show existing coming soon settings, switching to public/private and saving settings should remove the option:

http://calypso.localhost:3000/settings/general/<yourtestsite>.wo\rdpress.com?flags=coming-soon-v2

Should behave like production:

http://calypso.localhost:3000/settings/general/<yourtestsite>.wo\rdpress.com?flags=coming-soon-v2=false

e.g.

http://wordpress.com/settings/general/<yourtestsite>.wo\rdpress.com

props: @roo2 / @ramonjd (alot of code got squashed/rebased out of #45606 / #45896

[matticbot]

Test live: https://calypso.live/?branch=update/remove-coming-soon-option

[matticbot]

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

Sections (~28 bytes added 📈 [gzipped])

name      parsed_size           gzip_size
settings       +121 B  (+0.0%)      +28 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.

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.

[roo2]

tested with the feature flag on and off, it LGTM

[lsl]

Just a rebase, circle ci rerun seems unresponsive.