fix: Vendor class shop_data persistence is broken on save()

[shohag121]

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Closes

• Closes Vendor class "shop_data' persistence is broken - affects dokan_user_update_to_seller() #2077

How to test the changes in this Pull Request:

• Check issue Vendor class "shop_data' persistence is broken - affects dokan_user_update_to_seller() #2077

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• Code is not following code style guidelines
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