Add GTG feature flag

[asvinb]

Changes proposed in this Pull Request:

Closes https://linear.app/a8c/issue/GOOWOO-361/hide-ui-when-gtg-feature-flag-is-disabled

Replace this with a good description of your changes & reasoning.

Screenshots:

Detailed test instructions:

1. Enable the GTG feature flag by updating enabledFeatures in src/Admin/Admin.php to be [ 'google_tag_gateway' ]
2. Check that the GTG component is rendered in the Settings page.
3. Disable the GTG feature flag ( [] ).
4. Check that the GTG component is not rendered in the Settings page and there's no mention of GTG when an Ads account is not connected in the settings page.
5. Also check the GTG tour is not rendered if the feature flag is not set and the onboarding success modal does not mention GTG.

Additional details:

Changelog entry

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.8%. Comparing base (84c06b6) to head (247cf57).
⚠️ Report is 1 commits behind head on feature/GOOWOO-263-google-tag-gateway.

Files with missing lines	Patch %	Lines
src/Admin/Admin.php	0.0%	3 Missing ⚠️
...rnal/DependencyManagement/AdminServiceProvider.php	0.0%	2 Missing ⚠️
...ges/product-feed/submission-success-guide/index.js	80.0%	1 Missing ⚠️

Additional details and impacted files

@@                            Coverage Diff                             @@
##             feature/GOOWOO-263-google-tag-gateway   #3162      +/-   ##
==========================================================================
- Coverage                                     67.5%   66.8%    -0.8%     
- Complexity                                       0    5116    +5116     
==========================================================================
  Files                                          357     868     +511     
  Lines                                         5812   26227   +20415     
  Branches                                      1437    1444       +7     
==========================================================================
+ Hits                                          3924   17510   +13586     
- Misses                                        1717    8546    +6829     
  Partials                                       171     171              

Flag	Coverage Δ
js-unit-tests	67.6% <91.7%> (+<0.1%)	⬆️
php-unit-tests	66.5% <58.3%> (?)

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

Files with missing lines	Coverage Δ
js/src/constants.js	100.0% <100.0%> (ø)
js/src/utils/isFeatureEnabled.js	100.0% <100.0%> (ø)
src/Options/Features.php	90.2% <100.0%> (ø)
...ges/product-feed/submission-success-guide/index.js	62.1% <80.0%> (+3.7%)	⬆️
...rnal/DependencyManagement/AdminServiceProvider.php	0.0% <0.0%> (ø)
src/Admin/Admin.php	0.0% <0.0%> (ø)

... and 507 files with indirect coverage changes

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[ankitguptaindia]

QA Status: Need Feedback/fixes. ⚠️

Summary

When the GTG feature flag is disabled by setting enabledFeatures => [] in src/Admin/Admin.php, the UI components are correctly hidden, but GTG scripts continue to be injected into the frontend source code. I believe the feature flag should remove both UI setting AND script injection.

@asvinb Please let me know if this is intentional behaviour?

Steps to Reproduce

1. Open src/Admin/Admin.php
2. Set enabledFeatures to an empty array:

   'enabledFeatures' => [],

3. Save the file and refresh WordPress admin
4. Navigate to the Settings page
   • ✅ Expected: GTG component is not visible (this works correctly)
5. Visit the frontend website and view page source
   • ❌ Bug: GTG scripts are still present in the HTML:

     <script>
     (function(w,i,g){w[g]=w[g]||[];if(typeof w[g].push=='function')w[g].push.apply(w[g], i)})
                 (window,['AW-16732375809'],'google_tags_first_party');
     </script>
     <script src="/wp-content/plugins/google-listings-and-ads/vendor/google/gtg-ads/dist/measurement.php?id=AW-16732375809" async>
     </script>

Recording.1594.mp4

[asvinb]

@ankitguptaindia That's correct. GTG scripts should not be present on the FE. @jamesmorrison @jjgrainger Can you kindly take a look please? Thanks!