[Backport] - Same product quantity not increment when added with guest user

[niravkrish]

Original Pull Request

#21501

Description (*)

Fixed Issues (if relevant)

1. Same product quantity not increment when added with guest user. #21375: Same product quantity not increment when added with guest user

Manual testing scenarios (*)

1. Manual Testing

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[m2-assistant]

Hi @niravkrish. Thank you for your contribution
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[orlangur]

@niravkrish original commit author must be preserved

[orlangur]

@niravkrish pull request branch is still not fixed.

[sidolov]

@niravkrish , I am closing this PR now due to inactivity.
Please reopen and update if you wish to continue.
Thank you for the collaboration!

[m2-assistant]

Hi @niravkrish, thank you for your contribution!
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