FFWEB-3032: Support MSI - checking all inventory sources for export

[Rayn93]

• Solves issue:
  • FFWEB-3032
• Description:
  • Support MSI - checking all inventory sources during export feed
• Tested with Magento editions/versions:
  • For example: 2.4.6
• Tested with PHP versions:
  • For example: 8.1