Feature: Streamline the onboarding flow

[joemcgill]

Changes proposed in this Pull Request:

Closes #2458.

This feature branch includes fixes for the following issues:

• Onboarding: Hide WP.com connection card if already connected #2487
• Onboarding: Default stores to destination-based tax rates during onboarding #2491
• Onboarding: Remove Tax Rates Selection UI #2490
• Onboarding: Remove Language Setting UI #2489
• Onboarding: Remove Pre-Launch checklist UI #2492
• Onboarding: Move FAQs below the CTA button #2488
• Onboarding: Clean up settings API for pre-launch checklist items #2494
• Onboarding: Clean up unused MC settings data #2572
• Onboarding: Remove “Confirm store requirements” step if possible #2493

Additional details:

Changelog entry

[codecov]

Codecov Report

Attention: Patch coverage is 28.00000% with 18 lines in your changes missing coverage. Please review.

Project coverage is 62.7%. Comparing base (1c6a902) to head (a2a1e84).
Report is 15 commits behind head on develop.

Files with missing lines	Patch %	Lines
...src/components/paid-ads/asset-group/asset-group.js	0.0%	12 Missing ⚠️
.../free-listings/setup-free-listings/form-content.js	0.0%	1 Missing and 1 partial ⚠️
...c/components/stepper/step-content-actions/index.js	33.3%	1 Missing and 1 partial ⚠️
...ponents/free-listings/setup-free-listings/index.js	50.0%	1 Missing ⚠️
.../src/components/paid-ads/asset-group/faqs-panel.js	50.0%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             develop   #2631      +/-   ##
============================================
- Coverage       65.3%   62.7%    -2.6%     
============================================
  Files            474     319     -155     
  Lines          17893    5063   -12830     
  Branches           0    1233    +1233     
============================================
- Hits           11685    3173    -8512     
+ Misses          6208    1716    -4492     
- Partials           0     174     +174     

Flag	Coverage Δ
js-unit-tests	62.7% <28.0%> (?)
php-unit-tests	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...choose-audience-section/choose-audience-section.js	33.3% <ø> (ø)
...listings/configure-product-listings/checkErrors.js	100.0% <100.0%> (ø)
js/src/components/paid-ads/ads-campaign.js	0.0% <ø> (ø)
js/src/components/paid-ads/faqs-panel.js	66.7% <100.0%> (ø)
...rc/components/stepper/step-content-footer/index.js	50.0% <100.0%> (ø)
js/src/components/vertical-gap-layout/index.js	100.0% <ø> (ø)
js/src/data/action-types.js	100.0% <ø> (ø)
js/src/data/actions.js	7.9% <ø> (ø)
js/src/data/reducer.js	83.5% <ø> (ø)
js/src/data/resolvers.js	7.6% <ø> (ø)
... and 7 more

... and 775 files with indirect coverage changes

[mikkamp]

Just wanted to clarify that the failing unit test has already been resolved in PR #2626

We can ignore that here (no need to merge the latest changes into this branch).