Add target audiences and shipping times in the settings/general endpoint.

[jorgemd24]

Changes proposed in this Pull Request:

Part of #2146

As part of the new mechanism for syncing merchant data with Google Merchant Center, we need to make some GLA Options accessible, such as the target audience and shipping times.

This PR adds the target audience and shipping time to the response of wp-json/wc/v3/settings/general

Initially, my idea was to use the filter woocommerce_settings- . $group_id to add a new group of settings. However, this filter can only be used for Options (which should be fine for the target audience but not for the shipping times). Additionally, the filter woocommerce_settings- doesn't provide the Request Object param so I decided to use the filter rest_request_after_callbacks which makes it easier to verify if the request is made from the proxied endpoints.

https://github.com/woocommerce/woocommerce/blob/af03815134385c72feb7a70abc597eca57442820/plugins/woocommerce/includes/rest-api/Controllers/Version3/class-wc-rest-setting-options-controller.php#L79

Screenshots:

Detailed test instructions:

1. Get WC REST API credentials, or alternatively, you can use your sandbox and authorize your WPCOM App in WPCOM.
2. Make a request to GET /wp-json/wc/v3/settings/general?gla_syncable=1. If using the WPCOM proxy, use wpcom/v2/sites/YOUR_BLOG_ID/wc/v3/settings/general.
3. Verify that the response contains two new fields: gla_target_audience and gla_shipping_times.
4. Check that if the parameter gla_syncable=1 is not included in the URL, for example: GET /wp-json/wc/v3/settings/general, it will not add those two fields. Note: If you make the request from WPCOM, it will always add the query parameter.

Additional details:

Changelog entry

[codecov]

Codecov Report

Attention: Patch coverage is 61.90476% with 16 lines in your changes are missing coverage. Please review.

Project coverage is 64.1%. Comparing base (30bc13b) to head (8ceb779).
Report is 13 commits behind head on feature/google-api-project.

Additional details and impacted files

@@                      Coverage Diff                       @@
##             feature/google-api-project   #2342     +/-   ##
==============================================================
+ Coverage                          62.5%   64.1%   +1.5%     
+ Complexity                         4466    4450     -16     
==============================================================
  Files                               764     472    -292     
  Lines                             22581   18775   -3806     
  Branches                            543       0    -543     
==============================================================
- Hits                              14121   12031   -2090     
+ Misses                             8003    6744   -1259     
+ Partials                            457       0    -457     

Flag	Coverage Δ
js-unit-tests	?
php-unit-tests	64.1% <61.9%> (+0.1%)	⬆️

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

Files	Coverage Δ
...ependencyManagement/IntegrationServiceProvider.php	0.0% <0.0%> (ø)
src/DB/Query/ShippingTimeQuery.php	31.2% <50.0%> (+17.0%)	⬆️
src/Integration/WPCOMProxy.php	65.4% <67.7%> (-0.8%)	⬇️

... and 317 files with indirect coverage changes

[puntope]

LGTM ✅ Thanks @jorgemd24

When gla_syncable=1

I left a comment regarding the since tag, but approved in advance.

[puntope]

Missed @since param

[puntope]

Actually since all the class is new maybe we can add it at the top of the class