Require upgrade to become a seller

<img width="1360" height="780" src="https://mymarketplacebuilder.com/wp-content/uploads/2022/08/Dashboard_-_When_Buyer_attempts_to_become_a_seller-1.png" class="attachment-full size-full wp-post-image" alt="" decoding="async" fetchpriority="high" srcset="https://mymarketplacebuilder.com/wp-content/uploads/2022/08/Dashboard_-_When_Buyer_attempts_to_become_a_seller-1.png 1360w, https://mymarketplacebuilder.com/wp-content/uploads/2022/08/Dashboard_-_When_Buyer_attempts_to_become_a_seller-1-300x172.png 300w, https://mymarketplacebuilder.com/wp-content/uploads/2022/08/Dashboard_-_When_Buyer_attempts_to_become_a_seller-1-1024x587.png 1024w, https://mymarketplacebuilder.com/wp-content/uploads/2022/08/Dashboard_-_When_Buyer_attempts_to_become_a_seller-1-768x440.png 768w" sizes="(max-width: 1360px) 100vw, 1360px" />

Restricts buyers from being able to become sellers and post listings unless they upgrade their membership or subscription plan.