M2.3.6, v1.2.2: Cannot update configurable products via Rest API

ISSUE:

After installing BSS Inventory Report, we cannot update configurable products via Rest API.

This is the API endpoint we use:

rest/V1/products/{sku}

Method: PUT

And we get this error:

    "message": "Can't check requested quantity for products without Source Items support.",

After disabling the module, this API works fine without any error.

SOLUTION:

Our module is getting product saleable qty directly but configurable product type cannot be obtained like that. In default Magento, it will get by item so you won't get this error.

To resolve the issue, please edit the file app/code/Bss/InventoryReport/Model/MultiInventorySource/StockAndSourceProcessor.php as below: 

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