[Backport releases/28.x] Fix #7622 Shopify product export child-item variant handling

[tVisionDeb]

Summary

Backport of PR #7689 (merged to microsoft:main on 29 April 2026).

Cherry-picks the fix for issue #7622 onto releases/28.x. The fix prevents Shopify product export from creating unwanted variants for items that were added as a Shopify variant via the child-item mapping.

HS Code / tariff tests (part of a separate feature not present in releases/28.x) were excluded from the cherry-pick as they are unrelated to this fix.

Work Item(s)

Fixes AB#4326

[github-actions]

Issue #7622 is not valid. Please make sure you link an issue that exists, is open and is approved.

[tVisionDeb]

This PR is mostly a straight backport of #7689, but one additional fix was needed for the test to pass in 28.x CI.

Additional fix (commit e878f5e): The test uses [HttpClientHandler]\ for HTTP mocking, but \Shpfy Communication Mgt.\ (codeunit 30103) is declared \SingleInstance = true. Every call to \CreateShop()\ sets \IsTestInProgress = true\ on that singleton, which routes all HTTP calls through the old \OnClientSend/\OnGetContent\ event system instead of \HttpClient.Send(). Since [HttpClientHandler]\ only intercepts at \HttpClient.Send(), no mock response was ever set - resulting in the empty response that caused the 'no JSON for productUpdate' CI failure across all 17 locales.

The fix adds \CommunicationMgt.SetTestInProgress(false)\ to \InitializeProductExport(), matching the existing pattern in \ShpfyCreateItemAPITest\ (which has the comment 'Disable Event Mocking' for exactly this reason). The original test was validated in an isolated codeunit where \CreateShop()\ had not previously been called; when merged into the existing codeunit 139601 the singleton state from earlier tests in the same session caused the failure.

[tVisionDeb]

To add context on the testing approach: the Shopify connector originally mocked HTTP via event subscribers on \OnClientSend/\OnGetContent, controlled by the \IsTestInProgress\ flag. Newer test codeunits (written after BC introduced [HttpClientHandler]) call \SetTestInProgress(false)\ explicitly to opt out of the old event system - you can see the pattern in \ShpfyCreateItemAPITest\ and others.

In main, the test for #7689 was written in a fresh codeunit that started with a clean singleton state. In this backport it was placed into the existing codeunit 139601, which was written before the [HttpClientHandler]\ pattern existed and whose setup code never resets the flag. The 28.x backport therefore straddles the transition between the two approaches, and the \SetTestInProgress(false)\ call is the bridge.